Minimizing oil leakage from rocking journal bearings of two-stroke cycle engines
AssigneeAchates Power, Inc.
InventorsJohn M. Kessler, Clark A. Klyza
Life of this patent
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Abstract
A rocking journal bearing is provided in a piston coupling mechanism of a two-stroke cycle engine. The bearing includes a sleeve and a wristpin constructed with two sets of eccentrically-disposed bearing surfaces which alternate in accepting a compressive load during an operational cycle of the bearing. The sleeve includes a network of grooves to transport oil to the bearing surfaces. Lubricating oil flow through the bearing is minimized by limiting provision of pressurized oil from the wristpin to the network of grooves to portions of the cycle when one or the other of the sets of bearing surfaces receives the compressive load.
Claims6
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,
- each outlet passage in each journal segment is positioned between two of said axial oil grooves when a rotational position of the wristpin with respect to the bearing sleeve is 0° as would occur when a load transfer point of the rocking journal bearing is traversed during said rocking oscillation.
A two-stroke cycle, opposed-piston engine having first and second rotatable crankshafts, one or more cylinders each with a first piston interconnected by a connecting rod with the first crankshaft and a second piston opposing the first piston and interconnected by a connecting rod with the second crankshaft, a first rocking journal bearing situated between the first piston and its connecting rod and including a plurality of sets of bearing surfaces, a second rocking journal bearing situated between the second piston and its connecting rod and including a plurality of sets of opposed bearing surfaces, in which each rocking journal bearing includes:
- 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,
- each oil outlet passage in each journal segment is positioned between two of said axial oil grooves when a rotational position of the wristpin with respect to the bearing sleeve is 0° as would occur when a load transfer point of the rocking journal bearing is traversed during said rocking oscillation.
Dependencies are inferred from the claim text.