EHL film thickness in a grooved ball bearing

Elastohydrodynamic film thickness, contact ellipse and pressure for a grooved ball bearing, using the Hamrock-Dowson regression.

✓ validated against legacyoriginal: /calculators/e12_3.htm

EHL film thickness in a grooved ball bearing — original diagram from /calculators/e12_3.htm

Ball modulus, E₁GPaRace modulus, E₂GPaBall Poisson ratio, ν₁Race Poisson ratio, ν₂Ball radius x, R₁ₓmmBall radius y, R₁ᵧmmGroove radius x, R₂ₓmmRace radius y, R₂ᵧmmRadial load, PNNumber of balls, zRotational speed, nrpmViscosity, ηPa·sPressure-viscosity coefficient, α1/GPa

Central film thickness, hc0.1 µm

Mean contact pressure, pₘ0.98 GPa

Max contact pressure, pₘₐₓ1.48 GPa

Contact ellipse semi-axis a0.13 mm

Contact ellipse semi-axis b1.22 mm

Reduced modulus, E'230.77 GPa

Reduced radius, R5.08 mm

Dimensionless speed parameter5.2

Dimensionless load parameter305.38

Dimensionless film parameter0.49

Method & references

Hamrock-Dowson EHL film thickness regression for elliptical (point) contacts, applied to a grooved ball bearing.

The computation is a literal port of the original client-side JavaScript from /calculators/e12_3.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

EHL film thickness in a grooved ball bearing — Engineering ABC