This study presents a computer simulation to reveal the mechanism that the rolling piston of the rolling-piston type rotary compressors decreases effectively the power losses due to mechanical frictions. It is assumed from a previous experimental study that a fluid lubrication is formed between the rolling piston and the crankpin. The oil viscosity coefficient is given on the basis of experiments on oil pressure and temperature. The frictional state at the other pairs of machine elements is classified into two representative boundary frictions. Their frictional coefficients are determined numerically form the experimental data on the mechanical efficiency and the rolling-piston mean velocity, thus the power losses due to mechanical frictions can be calculated. To examine the calculated results, the computer simulations of other possible cases are presented. To confirm the validity of the calculated frictional coefficients, the rolling-piston mean velocity different operating conditions is calculated and the calculated results are compared with experimental ones.
