Patent ID: 9581187
Date: 2017-02-28
CPC Classifications: F01B,F01M,F02B,F02F,F16C,F16J

Claim:
1. A rocking journal bearing for a two-stroke cycle engine, comprising: a bearing sleeve including a generally cylindrical bearing surface with a plurality of axially-spaced, eccentrically-disposed surface segments separated by circumferential oil grooves in the bearing surface for transporting oil in a circumferential direction of the bearing surface; a plurality of circumferentially-spaced, axial oil grooves in the bearing surface that run across the surface segments and intersect the circumferential oil grooves for transporting oil in an axial direction of the bearing surface; a wristpin including a plurality of axially-spaced, eccentrically-disposed journal segments engaged for rocking oscillation with corresponding surface segments; and, an oil-receiving space in the wristpin with oil outlet passages acting through the journal segments for delivering oil to the bearing surface; in which, there are no oil outlet passages in the wristpin that are aligned with the circumferential oil grooves in the bearing surface; and, at least one oil outlet passage in each journal segment is positioned to cross at least one axial oil groove during said rocking oscillation; wherein, the plurality of journal segments includes a first journal segment formed in an intermediate portion of the wristpin, between two second journal segments and the two second journal segments are formed on opposite ends of the wristpin, on respective sides of the first journal segment; positioning of a first oil outlet passage locates the first oil outlet passage in the first journal segment at a first arcuate distance from one side of a cut plane containing the longitudinal axis of the wristpin and a radius forming an axis of an oil inlet passage in the wristpin for transporting oil to the oil-receiving space; and, positioning of two second oil outlet passages locates each second oil passage in a respective one of the second journal segments at a second arcuate distance from the opposite side of the cut plane; in which the first and second arcuate distances are in opposite directions; and, wherein, when a rotational position of the wristpin relative to the sleeve is at a load transfer point of the rocking journal bearing, the first and second oil outlet passages are positioned between first and second axial oil grooves, with the first oil outlet passage being relatively nearer to the first axial oil groove, and the second oil outlet passages being relatively nearer to the second axial oil groove.