COMPRESSO ERMETICO CON PISTONE ROTOLANTE RUOTANTE

The subject of the present invention is a sealed compressor with a rotating piston 50 of annular cross section, containing a crankshaft 60 with an eccentric portion 60a. The piston 50 rotates about the eccentric portion 60a of the crankshaft 60, all enclosed in the cylindrical chamber of a cylinder block. The piston 50 acts in combination with a sliding blade to divide the cylindrical chamber into inlet and exhaust zones. These zones have internal pressures lower than that of the oil elsewhere inside the shell of the compressor during the greater part of the cycle of rotation of the piston 50. Consequently, the oil passes through small spaces between the annular end faces of the piston 50 and the end walls of the cylindrical chamber in order to lubricate and seal the components of the compressor. By providing a rolling piston with a high ratio between the external and internal diameters (> 1.63), the radial travel of the lubricating oil is increased. In this way the flow of lubricating oil is reduced without the inconvenience of the conventional procedure for reducing the flow of oil in which the annular faces are placed closer to the end walls of the chamber causing increased wear. In addition, the crankshaft has an end portion 60b which has a radius Rr that satisfies the condition: 2Rr > Rr + Ec + Ro where Rr is the internal diameter of the piston 50a, Ec is the eccentricity of the eccentric portion 60a of the crankshaft 60 and Ro is the radius of the eccentric portion. (Fig. 4c)