Lubrication Flashcards
Kinematic Visc
ν = μ / ρ
Dynamic Visc
μ = (F / A) / (U / h)
Abs. viscosity @ given P
μ p = μK * exp(Υ*P)
μK - abs visc at atm pressure
Y - (gamma) pressure coefficient of viscosity
P - applied pressure
Load capacity in journal bearing
P = W / (LD)
Bearing parameter journal bearing
μ N / P
PV factor
P * V
Friction force #1, journal
F = (μ A U) / h
Contact area, journal bearing
Area = 2pi R L
or
Area = pi D L
Velocity, journal bearing
V = 2pi R n
or
V = pi D n
Height is equivalent to …. in journal bearings
radial clearance, c
Radial clearance, journal
c = (bearing diam. - shaft diam.) / 2
Friction force #2, journal
F = Tf / R
Tf is friction torque
Tf in friction force eqs, journal
Tf = (4(pi)^2 μ n R^3 L) / c
Clearance ratio, journal
R / c
Coefficient of friction, Petroff’s eqs, journal
f = 2(pi)^2 (μ n / P) (R / c)
aka f = 2(pi)^2 * (bearing parameter) * (clearance ratio)