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US 4,535,682 AGranted
Pistons
AssigneeAe PLC
InventorsJohn G. Collyear, David A. Parker
Life of this patent
Estimating the term…
Abstract
A piston for an engine or motor has a skirt which includes two portions which are urged towards an associated cylinder during the various strokes of the working cycle. Each portion is provided with a bearing surface or surfaces for sliding engagement with the associated cylinder during reciprocation. The piston is provided with formations which pass lubricant to and over the bearing surfaces.
Claims47
A piston for reciprocation in a cylinder of an internal combustion engine wherein lubrication with an associated cylinder is provided by an oil film, comprising
- a crown,
- a gudgeon pin bore,
- a ring belt,
- a first generally cylindrical skirt portion to one side of a plane including the piston axis and the gudgeon pin bore axis,
- a second generally cylindrical skirt portion to the other side of said plane,
- said skirt portions being attached to the ring belt,
- a small number of discrete bearing surfaces formed on the first and second skirt portions,
- each of said skirt portions having an associated one of said skirt portions therearound and being spaced radially outwardly of the associated one of said skirt portions by a small distance,
- a circumferentially extending front edge to each bearing surface,
- a circumferentially extending rear edge to each bearing surface,
- generally axially extending side edges interconnecting the front and rear edges of each bearing surface,
- a shallow hydrodynamic ramp connecting each said circumferential front edge to the surrounding skirt portion, the end of said ramp remote from the associated bearing surface being spaced from the surface in a radial direction by less than 125 microns.
- a shallow hydrodynamic ramp connecting each said circumferential rear edge to the surrounding skirt portion, the end of said ramp remote from the associated bearing surface being spaced from the surface in a radial direction by less than 125 microns, the surrounding skirt portions providing retained oil said small distance from said bearing surfaces and said ramps co-operating with the cylinder to force a thin oil film over the bearing surfaces during motion of the piston relative to the cylinder to hydrodynamically lubricate said bearing surfaces as the bearing surfaces transmit lateral thrust from the piston to the co-operating cylinder.
10 more elements
A piston for reciprocation in a cylinder of an internal combustion engine wherein lubrication with an associated cylinder is provided by an oil film, comprising
- a crown,
- a gudgeon pin bore,
- a ring belt,
- a first generally cylindrical skirt portion to one side of a plane including the piston axis and the gudgeon pin bore axis,
- a second generally cylindrical skirt portion to the other side of said plane,
- said skirt portions being attached to said ring belt,
- at least three discrete bearing surfaces formed on each of the first and second skirt portions,
- each of said at least three bearing surfaces having an associated skirt portion therearound and being spaced radially outwardly of the associated skirt portion by a distance of less than 125 microns,
- shallow hydrodynamic ramps extending from the associated skirt portion to each bearing surface,
- two of said at least three bearing surfaces and associated ramps forming a row and being aligned and being spaced or opposite sides of a plane including the piston axis and normal to the gudgeon pin bore axis,
- the at least one remaining bearing surface and associated ramps being spaced axially from said two of said at least three bearing surfaces and associated ramps, the at least three bearing surfaces on each skirt portion transmitting lateral thrust from the piston to the co-operating cylinder with the surrounding skirt portions providing retained oil said distance from said bearing surfaces and said shallow hydrodynamic ramps co-operating with the cylinder to force a thin oil film over the bearing surfaces during motion of the piston relative to the cylinder to hydrodynamically lubricate said at least three bearing surfaces.
8 more elements
A piston for reciprocation in a cylinder of an internal combustion engine wherein lubrication withan associated cylinder is provided by an oil film, comprising
- a crown,
- a gudgeon pin bore,
- a ring belt,
- a first generally cylindrical skirt portion to one side of a plane including the piston axis and the gudgeon pin bore axis,
- a second generally cylindrical skirt portion to the other side of said plane,
- said skirt portions being attached to said ring belt,
- a small number of discrete bearing surfaces formed on the first and second skirt portions, each said bearing surface having generally circumferentially extending front and rear edges and generally axially extending side edges extending between said front and rear edges,
- shallow hydrodynamic ramps connecting each said front and rear generally circumferential edge to the surrounding skirt portion,
- each said discrete bearing surface being surrounded by an associated one of said skirt portions and being spaced radially outwardly of said associated skirt portion by less than 125 microns, the surrounding skirt portions providing retained oil closely adjacent the bearing surfaces and said ramps co-operating with the cylinder to force a thin oil film over the bearing surfaces during motion of the piston relative to the cylinder to hydrodynamically lubricate said bearing surfaces as the bearing surfaces transmit lateral thrust from the piston to the co-operating cylinder.
6 more elements
A piston for reciprocation in a cylinder of an internal combustion engine wherein lubrication with an associated cylinder is provided by an oil film, comprising
- a crown,
- a gudgeon pin bore,
- a ring belt,
- a first generally cylindrical skirt portion to one side of a plane including the piston axis and the gudgeon pin bore axis,
- a second generally cylindrical skirt portion to the other side of said plane,
- said skirt portions being attached to said ring belt,
- a small number of discrete bearing surfaces formed on the first and second skirt portions,
- each said discrete bearing surface being surrounded by an associated one of said skirt portions and being spaced radially outwardly of the associated one of said skirt portions by a small distance,
- a circumferentially extending front edge to each bearing surface,
- a circumferentially extending rear edge to each bearing surface,
- generally axially extending side edges interconnecting the front and rear edges of each bearing surface,
- a shallow hydrodynamic ramp having an angle of less that 1.5.degree. and connecting each said circumferential front edge to the surrounding skirt portion,
- a shallow hydrodynamic ramp having an angle of less than 1.5.degree. and connecting each said circumferential rear edge to the surrounding skirt portion, said ramps co-operating with the cylinder to force a thin oil film over the bearing surfaces during motion of the piston relative to the cylinder to hydrodynamically lubricate said bearing surfaces as the bearing surfaces transmit lateral thrust from the piston to the co-operating cylinder and the surrounding skirt portions providing retained oil said small distance from said bearing surfaces.
10 more elements
A piston for reciprocation in a cylinder of an internal combustion engine wherein lubrication with an associated cylinder is provided by an oil film, comprising
- a crown,
- a gudgeon pin bore,
- a ring belt,
- a first generally cylindrical skirt portion to one side of a plane including the piston axis and the gudgeon pin bore axis,
- a second generally cylindrical skirt portion to the other side of said plane,
- said skirt portions being attached to said ring belt,
- at least three discrete bearing surfaces formed on each of the first and secnd skirt portions,
- each of said at least three bearing surfaces having an associated skirt portion therearound and being spaced radially outwardly of the associated skirt portion by a small distance,
- hydrodynamic ramps having an angle of less than 1.5.degree. extending from the associated skirt portion to each bearing surface,
- two of said at least three bearing surfaces and associated ramps forming a row and being aligned and being spaced on opposite sides of a plane including the piston axis and normal to the gudgeon pin bore axis,
- the at least one remaining bearing surface and associated ramps being space axially from said two of said at least three bearing surfaces and associated ramps, the at least three bearing surfaces on each skirt portion transmitting lateral thrust from the piston to the co-operating cylinder with the surrounding skirt portions providing retained oil said small distance from said bearing surfaces and said hydrodynamic ramps co-operating with the cylinder to force a thin oil film over the bearing surfaces during motion of the piston relative to the cylinder to hydrodynamically lubricate said at least three bearing surfaces.
8 more elements
A piston for reciprocation in a cylinder of an internal combustion engine wherein lubrication with an associated cylinder is provided by an oil film, comprising
- a crown,
- a gudgeon pin bore,
- a ring belt,
- a first generally cylindrical skirt portion to one side of a plane including the piston axis and the gudgeon pin bore axis,
- a second generally cylindrical skirt portion to the other side of said plane,
- said skirt portions being attached to said ring belt,
- at least three discrete bearing surfaces formed on each of the first and second skirt portions,
- each of said at least three bearing surfaces having an associated skirt portion therearound and being spaced radially outwardly of the associated skirt portion by a small distance,
- shallow hydrodynamic rmps extending from the associated skirt portion to each bearing surface, the ends of said ramps remote from the associated bearing surfaces being spaced from the associated surface in a radial direction by less than 125 microns,
- two of said at least three bearing surfaces and associated ramps forming a row and being aligned and being spaced on opposite sides of a plane including the piston axis and normal to the gudgeon pin bore axis,
- the at least one remaining bearing surface and associated ramps being spaced axially from said two of said at least three bearing surfaces and associated ramps, the at least three bearing surfaces on each skirt portion transmitting lateral thrust from the piston to the co-operating cylinder with the surrounding skirt portions providing retained oil said small distance from said bearing surfaces and said shallow hydrodynamic ramps co-operating with the cylinder to force a thin oil film over the bearing surfaces during motion of the piston relative to the cylinder to hydrodynamically lubricate said at least three bearing surfaces.
8 more elements
A piston according to claim 20, 21, 23, 36 or 37 wherein said bearing surfaces are generally rectangular in shape.
Dependencies are inferred from the claim text.