Design & selection

Bearings

General bearing knowledge and the design tools that support it. For the specialist gas-bearing core — aerostatic, spiral-groove and narrow-groove — see Gas Bearings.

Calculators

Hydrostatic bearing — wedge-film thrust padDimensionless load, stiffness and load-sensitivity for a wedge-film hydrostatic thrust pad, from the film-thickness ratio h1/h0.✓ validatedHydrostatic bearing — shallow-recess thrust padDimensionless load, stiffness and load-sensitivity for a shallow-recess hydrostatic thrust pad, from the recess-area and film-thickness ratios.✓ validatedHydrostatic 4-chamber thrust bearingLoad, stiffness, flow and power for a hydrostatic 4-chamber thrust bearing, with a choice of capillary, orifice, or fixed-flow restrictor.✓ validatedHydrostatic journal bearing, externally pressurizedLoad, stiffness, flow and power for an externally pressurized hydrostatic journal bearing — separated or connected recess elements, with a choice of restrictor.✓ validatedPartially grooved hydrostatic journal bearingLoad and flow for a partially grooved, externally pressurized hydrostatic journal bearing with k grooves, by numerical summation around the circumference.✓ validatedPivot bearing — contact pressure and friction torqueContact pressure (Hertz, with interpolation to a plastic/Brinell regime at high loads) and friction torque/power for a pivot bearing ("boltaats").✓ validatedTilting-pad (Michell) bearing — rectangular padLoad capacity, friction coefficient and film-thickness/eccentricity numbers for a rectangular Michell tilting-pad bearing, sized as a compromise between minimum friction and maximum film thickness.✓ validatedHydrodynamic journal bearingSommerfeld number, attitude angle, friction, load capacity, stiffness, side leakage and frictional heating for a finite-length hydrodynamic journal bearing. Unlocked from the legacy demo gate; general in shaft diameter, clearance and film thickness.✓ validatedHydrodynamic bearing under shock (impulsive) loadDimensionless and dimensional impulse capacity of a finite-length hydrodynamic journal bearing (π-film boundary condition) subjected to a shock/impact load.✓ validatedDesign of a hydrodynamically lubricated plain bearingSommerfeld number, attitude angle, friction and flow numbers, plus load capacity, friction coefficient and lubricant flow for a hydrodynamically lubricated plain (journal) bearing, from length ratio, eccentricity, clearance ratio, radius, speed and viscosity.✓ validatedJournal bearing — oil flow / pressure dropPressure drop across a journal bearing film needed to produce a prescribed axial (cooling) flow rate, from shaft diameter, bearing length, radial clearance, eccentricity and viscosity.✓ validatedStatic load capacity of polymer (thermoplastic) bearingsElastic indentation, contact geometry, load capacity and stiffness of a thermoplastic sliding bearing bush from shaft diameter, bearing length, wall thickness, modulus of elasticity, radial clearance and allowable contact pressure.✓ validatedLoad capacity and stiffness of guide ringsContact geometry, load capacity and stiffness of a resilient thermoplastic guide (wear) ring supporting a piston/rod, from piston diameter, ring width/thickness, elastic indentation, radial clearance and modulus of elasticity. Unlocked from the legacy demo gate; general in shaft diameter and indentation.✓ validatedStatic load rating of a deep-groove ball bearing (Hertz)Elliptical (Hertzian) contact pressure for a prescribed bearing load, and the ISO 76:1987 basic static load rating C0 for a prescribed maximum contact pressure, from ball and raceway elastic properties and curvatures.✓ validatedFriction in a ball-cage linear guideHertzian contact stiffness and pressure of a single ball in a ball-cage linear guide (loaded at 45° to the guide axis), plus the resulting sliding friction force and coefficient.✓ validated

Background

Bearings — Engineering ABC