Search Results

With consideration of the importance (for oil passing and blow-by) of the issue of three-dimensional deformation of piston rings in a cylinder due to either installation stress, or operational gas, friction, and thermal loads the subject of piston ring distortions still generates continuing interest. The current paper demonstrates application of a mathematical model developed in the former works of the authors for analysis of the distortions of arbitrary cross-section rings loaded by tangential force. Applications of the model to the several typical cross-sections are given for illustration. The work is a necessary step for the development of a comprehensive three-dimensional theory of piston ring installation and operational distortions.

The paper is a step in an ongoing work targeted at the development of an engineering methodology to estimate sealing properties of a piston ring, and for the development of ring design guidelines. This work is necessary because the sealing properties of a ring significantly affect oil passing and blow by in the reciprocating air compressors and engines. It is known that the sealing function of a piston ring depends on the ring's ability to elastically deform in its plane under its own tension by conforming to the deviations of the cylinder bore. At the same time, if it has an asymmetrical cross section, the ring fitted in the cylinder bore is subjected to the additional, three-dimensional, distortions called twist. This type of cross section is usually imparted to the ring to further improve its sealing functions by interlocking (because of twist) between the piston groove and the cylinder wall.