| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the generation of heat and the occurrence of seizure due to slide friction between a piston and cylinder occasioned especially by the increase of a speed by a method wherein an oil guide groove communicated with the interior of a case is formed in the outer periphery of a piston and a part inputted and outputted from the other end surface side of a cylinder block or the inner periphery of the cylinder block and a part, though which a part of a piston is inputted and outputted from the other end face side. SOLUTION: In addition to a conventional seal land 12, an outer peripheral groove 14 and an oil guide groove 13, inclined based on the reciprocating direction of a piston assembly 10 and communicated with a case drain 39 from the outer peripheral groove 14, are formed. This constitution, since oil leaking from the seal land 12, lubricates and cools the whole periphery of the piston 11 from the high pressure side of the piston 10 to the case drain 39 side, prevents the generation of heat and the occurrence of seizure due to slide friction even when the piston 11 is positioned eccentrically in a cylinder hole 22 by a centrifugal force through high speed rotation, and provides a cooling effect.</p> |
