Piston apparatus, stirling engine, external combustion engine, and fluid device

摘要

A piston apparatus which configures an air bearing by introducing a compressed working media into an inside of a piston, and ejecting the working media from plural holes arranged on a circumferential portion of the piston into a clearance between the piston and the cylinder, which prevents a back-flow of the working media in the piston to a working space, and which readily secures reliability and longevity is provided. The piston apparatus is applied to an external combustion engine 10, and includes a piston main body 211, a pressure-accumulating chamber 212 that is formed inside the piston main body, an introduction portion 214 that serves to introduce the compressed working media into the pressure-accumulating chamber, holes 216 that are arranged on a circumferential portion 211b of the piston main body and runs from the pressure-accumulating chamber to the clearance between the piston main body and the cylinder 22 of the external combustion engine, wherein the introduction portion is arranged to be communicable in an introduction direction to the pressure-accumulating chamber of the working fluid and an opposite direction of the introduction direction, and a channel resistance in the opposite direction in the introduction portion is larger than in the introduction direction.