HEAT BARRIER FOR REFRIGERATION COMPRESSOR PISTON

摘要

A piston intended for use in refrigeration compressors and other applications wherein a heat barrier is provided in the piston skirt between the head of the piston and the wrist pin. The heat barrier substantially reduces the conduction of heat from the higher temperature piston head to the wrist pin bearing surfaces, which would otherwise result in rapid wear of the wrist pin bearings and ultimate failure of the compressor. The heat barrier preferably comprises a pair of openings extending through the wrist pin bosses in close proximity to the wrist pin holes thereby partially thermally isolating the wrist pin holes from the head of the piston. The openings are spaced on opposite sides of an axial line extending from the piston head to the wrist pin holes so that there remains a bridge of the piston skirt material to provide the necessary support for hydraulic loads that occur when the compressor slugs. The openings in the wrist pin bosses also provide a passage for lubricant which is pumped through them by the ram pressure that is developed on the piston return stroke. The lubricant acts as a cooling medium to cool the wrist pin bearing surfaces.