Piston ring
AssigneeNtn Corporation
InventorKen Yasuda
Life of this patent
Estimating the term…
Abstract
To provide a piston ring having superior wear resistance and causing less wear damage of a cylinder. A piston ring 1 is used in a reciprocating compressor that compresses gas. The piston ring 1 is formed of a resin composition containing polyetheretherketone resin as a main component. The melt viscosity of the polyetheretherketone resin at the shear rate of 1,000/s and the temperature of 400° C. is 200-550 Pa·s based on a measuring method defined in ISO 11443. The resin composition contains 5-25 vol % of carbon fiber and 5-25 vol % of a solid lubricant, relative to the whole of the resin composition. The solid lubricant includes at least one of PTFE resin and graphite.
Claims2
A piston ring used in a hydrogen gas reciprocating compressor that compresses hydrogen gas, wherein:
- the piston ring is formed of a resin composition containing polyetheretherketone resin as a main component;
- where melt viscosity of the polyetheretherketone resin measured at a shear rate of 1,000/s and a temperature of 400° C. is 270-550 Pa·s based on a measuring method defined in ISO 11443,
- the piston ring is a heat-treated body of an injection-molded body of the resin composition,
- the piston ring has an endothermic peak in a range of 150-330° C., in addition to the endothermic peak due to a point at which the polyetheretherketone resin melts in a differential scanning calorimetry,
- having a sulfur content of 250 ppm or less,
- the resin composition does not contain polyphenylene sulfide resin, and contains 5-25 vol % of carbon fiber and 5-25 vol % of a solid lubricant, relative to the volume of the resin composition,
- the solid lubricant comprises at least one component selected from polytetrafluoroethylene resin and graphite, and
- the carbon fiber has an average fiber length of 20-200 μ.
Dependencies are inferred from the claim text.