Superposition of pivoted pad slider bearing and squeeze film fluid mechanics for heavily cyclically loaded machine elements

Claim 2

CLAIM 2 A hydrodynamic bearing assembly for operation in a machine which subjects the relatively sliding surfaces of said bearing to loads which fluctuate in magnitude and direction during the load cycle of said machine, wherein said bearing assembly comprises a pivoted pad slider bearing adapted to permit formation of an optimally shaped converging wedge oil film between two relatively sliding surfaces of roughly equal radius of curvature by permitting the sliding surface of the pivoting pad to tilt over a small range of angles about a pivot point or line so that the tilt angle between the pivoting pad surfaces and a surface sliding relatively to said pad surface establishes an oil wedge film pressure distribution having a moment balance about said pivot point or line, the structural relations between said pivoting pad and its supporting structure being such that the oil wedge film supporting surface of said pivoted pad deforms so that this surface has radii of curvature under heavily loaded conditions which very nearly correspond on scales relevant to the hydrodynamic and hydrostatic fluid mechanics in the pivoted plane slider bearing to the radii of curvature of the relatively sliding surface which supports the other side of the oil film on which said bearing pad rides, clearance volumes in the bearing assembly fluid mechanically upstream of the relatively sliding surfaces providing lubricant reservoirs filled with lubricant to assure that said pivoted pad slider bearing operates fully flooded with lubricant, whereby the fluctuating loads of the machine periodically reverse the load on said pivoted pad slider bearing surface and clearances in the bearing assembly permit the oil film between said pad and its relatively sliding surface to be substantially thickened during said period of reverse loading, so that the interaction of the bearing parts and the lubricant is such that when the bearing pad is again placed under load during the load cycle of such machine, the relative approach of the surfaces separated by the oil film is strongly resisted by squeeze film pressures between these surfaces, at the same time that the wedge hydrodynamic fluid mechanics of quasi-statically loaded pivoted pad slider bearings acts, whereby the dynamic behavior of the bearing involves the superposition of squeeze film and pivoted pad slider bearing hydrodynamic effects.

Claim 3

CLAIM 3 The invention as set forth in Claim 1 and wherein the pivoted pad is hydrostatically supported.

Claim 4

CLAIM 4 The invention as set forth in Claim 1 and wherein the pivoted pad is elastomerically supported.

Claim 5

CLAIM 5 The invention as set forth in Claim 1 and wherein the pivoted pad is supported by a constrained liquid containing elastomeric pad.

Claim 6

CLAIM 6 The invention as stated in Claim 5 wherein the difference in pressures acting on the pivoted pad between its oil film surface and said liquid containing elastomeric pad produce bending moments which act to match the radii of curvature of said pad sliding surface to the relatively sliding surface to maximize the combined effects of squeeze film and pivoted pad slider fluid mechanics.

Claim 7

CLAIM 7 The invention as stated in Claim 1, wherein said pivoted pad surface is a section of the outer surface of a cylinder, wherein the surface sliding relatively to said pad is a cylindrical surface, wherein said pad is connected to a crankpin linkage having a wrist pin and said pivot for said pad surface is the central axis of said wrist pin, wherein the structural relations between the pivoted pad surface and its supporting structure supports said surface so that said surface is flexible in bending and strong in circumferential compression so that said pad surface deforms under load so that the axial and circumferential radii of curvature of said pad surface very nearly correspond on scales relevant to the hydrodynamic and hydrostatic fluid mechanics to the corresponding local radii of curvature of said relatively sliding cylindrical surface.

Claim 8

CLAIM 8 The invention as stated in Claim 1, wherin said pivoted pad surface is the outer surface of a piston skirt of a piston reciprocating in a cylinder, wherein said cylinder surface is the surface sliding relatively to said pad surface, wherein said piston is connected to a crankpin linkage having a wrist pin and said pivot for said piston skirt surface is the central axis of said wrist pin, wherein the structural relations between the pivoted pad piston skirt surface and its supporting structure in the piston make said surface flexible in bending and strong in circumferential compression so that said skirt surface deforms under load so that the axial and circumferential radii of curvature of said skirt surface very nearly correspond on scales relevant to the hydrodynamic and hydrostatic fluid mechanics to the corresponding local radii of curvature of said cylinder wall.

Claim 9

CLAIM 9 The invention as stated in Claim 2 and wherein the hydrostatic support of the pivoted pad comprises two curved hydrostatic film supporting surfaces separated by an oil film, where one of said hydrostatic surfaces is integral with the pivoting pad so that said pad sliding surface and said hydrostatic surface are connected by structural material, where said hydrostatic surface is connected to said pivoting pad surface by a multiplicity of holes through said material so that said holes supply pressurized oil to said hydrostatic support oil film to maintain said film against the forces on said support structure.

Claim 10

CLAIM 10 The invention as stated in Claim 1 and wherein the environment of said pivoting pad is a connecting rod bearing of a reciprocating crankpin assembly.

Claim 11

CLAIM 11 The invention as stated in Claim 1 and wherein the environment of said pivoting pad is the main bearing cap of an internal combustion engine.