Experimental Verification of Oil Whirl of Piston in Axial Piston Pump and Motor.

Abstract

Piston motion which interacts with lubrication characteristics including friction force between the piston and cylinder has been measured in order to prove the oil whirl phenomena in an axial piston pump and motor which had been found theoretically in the previous paper. The piston motion has been measured by means of eddy current displacement sensors, comparing with calculated results. It has been verified that the piston has whirled in the cylinder under certain operating conditions and specifications, similar to the oiI whirl phenomena as self-excited vibration in journal bearings. The phenomena have not occurred for wide clearance and short sealing part between the piston and the cylinder as the previous paper predicted them. The period of piston whirl has coincided with that of friction force variation.