Plain (Sleeve) Bearing Pressure and PV

ScopeProjected pressure P = W/(L D) and the PV factor P*V (V = pi D N/12 ft/min), the product that governs frictional heat and wear. An 800 lbf load on a 1 in journal in a 1.5 in bronze bushing at 300 rpm sees 533 psi, 79 ft/min, and PV 41,900 psi-ft/min - just under the ~50,000 limit for oil-impregnated sintered bronze, so it works with little margin; double the speed and PV blows past 83,000, out of range. The projected area L x D is used, not the wrapped area. The hydrodynamic film, temperature rise, and the material specific limits are the bushing maker's. A design aid; Machinery Handbook and the bearing maker govern.

Formula or tableP = W/(L D) (projected area); V = pi D N/12 ft/min; PV = P V. Oil-impregnated sintered bronze PV limit ~50,000 psi-ft/min.

Source and editionThe plain-bearing projected pressure P = W/(L D), surface velocity V = pi D N/12, and the PV factor with the bearing-material PV limits (Machinery's Handbook), by name; the plain-bearing counterpart to the rolling-bearing rating-life tiles.

Free accessThe projected pressure, surface velocity, and PV factor are standard published plain-bearing results; the load, diameter, length, and speed are the user's inputs, and the rated PV comes from the bushing material.

What governsEstimate. AHJ and licensed professional govern.

API field namesradial_load_lbf, journal_diameter_in, bearing_length_in, speed_rpm, projected_pressure_psi, surface_velocity_fpm, pv_factor

• Projected pressure P = W/(L D), projected area L x D not wrapped areaMachinery's Handbook
• PV factor PV = P V, must stay under the material's rated PV (~50,000 for oil-impregnated bronze)bearing-material data
• Scope static pressure/PV screen; hydrodynamic film, temperature rise, material limits are the maker'sscope of this tile