Piston ring structural body and method of mounting piston ring structural body

Abstract

The present invention provides a piston ring structural body composed of an outer ring continuously formed of a resinous material, an inner ring continuously formed of a resinous material and a ring tensile force applying member for pressing the outer ring radially outwards via the inner ring. The piston ring structural body has a construction wherein the outer ring continuously formed of polyimide is pressed outwards in the radial direction of the piston by a coil expander via the inner ring continuously formed of PTFE. A sliding face of the outer ring, which slides on a cylinder wall, is divided into upper and lower sliding faces, whose respective upper edge portions are provided with chamfers. A contact portion of the inner ring that contacts the coil expander is provided with an upper inclined face extending inwards and upwards and a lower inclined face extending inwards and downwards. The angles of inclination of the upper and lower inclined faces range from 30 DEG to 60 DEG .

Description

technical field [0001] The present invention relates to a piston ring structure for an internal combustion engine, and particularly relates to radially extending an outer ring continuously formed of a resin material through an inner ring continuously formed of a resin material without a cut by a ring tension providing member. Piston ring structure pressed to the outside. The invention also relates to a method for installing the piston ring structure. Background technique [0002] In Japanese Patent Application Laid-Open No. 9-280373, it is proposed to continuously form a piston ring of resin without notches for reducing the amount of leakage gas (the gas leaks into the crankcase through the gap between the piston ring and the cylinder) ). In the above-mentioned publication, it is proposed that the ring tension providing member composed of a metal spiral expander is continuously formed without a cut by using polytetrafluoroethylene (PTFE) as a fluorinated resin through an i...

AI Technical Summary

Problems solved by technology

However, the PV critical value of PTEF is low (the product of the actual pressure P and the sliding velocity V), so that the sliding part that slides on the cylinder wall does not have sufficient durability

Moreover, PTFE has a large coefficient of thermal expansion, so when the temperature rises, the pressure acting on the cylinder wall due to the elastic force of the spiral expander becomes larger, causing the problem of increased friction loss of the engine.

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