I was recently asked to review this important measurement guideline. PV is a means of measuring the performance capabilities of bearings. P is expressed as pressure or pounds per square inch on the projected bearing area. V is the velocity in feet per minute of the wear surface.
For sleeve bearings, the surface speed is Pi (π) x diameter x RPM ÷12 in inches. P is the load on the bearing in pounds, divided by the projected area in square inches. For sleeve bearings, the projected area is the length times the diameter of the bearing.
PV is obtained by multiplying the P x V as shown here:
3/4” shaft @341 RPM:
90 lb total load, bearing length 1”
V= 3.1416 (pi) x Shaft Diameter x RPM ÷ 12
Or 3.1416 x .750 x 341 ÷ 12 = 67 sfpm
P= Total Load ÷ projected area
Area = .750 ID x1.0 long = .75 in projected bearing area
P= 90 lbs ÷ .75 = 120 psi
PV = 120 psi x 67 fpm = 8040 PV
As long as you keep your application below the estimated PV as well as the known P and V you will successfully be able to utilize polymer bearings!
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