A bore portion for receiving a reciprocating piston

• Main Authors: Roland Paul Stark, Arup Kumar Gangopadhyay, Thomas Reddyhoff, Khizer Tufail, Sorin-Cristian Vladescu
• Format: Patent
• Language: English
• Published: 01.04.2020
• Subjects: ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES; BLASTING; COMBUSTION ENGINES; CYLINDERS; CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; PISTONS; SEALINGS; THERMAL INSULATION IN GENERAL; WEAPONS

A bore portion, eg a of cylinder or cylinder liner, for receiving a reciprocating piston, eg of an i.c. engine or a pump, comprises a plurality of axially spaced recesses 129 formed in a piston-facing surface of the bore portion at a number of axial positions, each recess 129 having a width W in the axial direction and a depth D perpendicular to the piston facing surface. The widths W of the recesses 129 reduce in each axial direction away from a mid-stroke position 103c and the depths D of the recesses 129 increase in each axial direction away from the mid-stroke position to improve lubrication and reduce friction. The total recess volume at each axial position may vary progressively along the axial length of the bore portion with the total recess volume increasing away from the mid-stroke position. The recesses 129 may be pockets of any shape, eg square, circular or rectangular, to trap lubricant, and may be made eg by casting, machining or laser honing.