Structural improvement, material selection and surface treatment for improved tribological performance of friction pairs in axial piston pumps: A review

Axial piston pumps have three important friction pairs (valve plate–cylinder, swashplate–slipper, and cylinder–piston interfaces), which are crucial to the performance and service life of the pumps. The friction pairs of the piston pumps are facing challenges due to the demands for high-performance piston pumps with high speeds, large flow rates, and higher pressures. This article provides an overview of studies on the wear mechanisms of the three friction pairs and a summary of current research seeking solutions for the friction pairs, including structural improvement, material selection, and surface treatment. Existing issues in the development of high-performance axial piston pumps are also discussed. This review article is delivered with an attempt to provide a reference for designing high-performance.