Lubrication analysis between piston and cylinder in hydraulic piston pump - effect of piston shape and circumferential groove

In this paper, a theoretical analysis is carried out to Study the effect of piston shape and circumferential groove on the lubrication characteristics between partially tapered piston and cylinder bore of hydraulic piston pumps. Analytic expressions for the pressure distribution, lateral force acting on the piston and leakage flow rate through the clearance are obtained solving one-dimensional Reynolds equation. The results showed that the tapered, length and groove location affect highly the pressure distributions, lateral forces and leakage. Partially tapered piston whose groove is located in tapered region is most effective because it reduces the possibility of hydraulic locking.