# Numerical - Basic dynamic capacity of bearing, given radial & axial force, rating life

Q.  A deep groove ball bearing rotating at 1200 r.p.m. is subjected to radial and an axial force of 2000 N and 1500 N respectively. What will be the basic dynamic capacity of bearing if 20,000 hours is the rating life?
(Consider radial factor = 0.55, Thrust factor = 2 & application factor = 1.5?

- Published on 19 Oct 15

a. 69.448 kN
b. 54.498 kN
c. 50.236 kN
d. 12.726 kN

#### Discussion

• Mamaru   -Posted on 01 Jun 16
Very interesting quation
• Sravanthi   -Posted on 01 Oct 15
Given: Speed = 1200 r.p.m, Lh10 = 20,000 hours, radial force = 2000 N, axial force = 1500 N, X =0.55, Y = 2, Ka = 1.5
a = 3 for ball bearing & assume V =1

L10 is the rating life of a group defined as number of revolutions completed by 90 % of group of bearings before the first evidence of fatigue failure appears.

Formula: 1) L10 = (Basic dynamic capacity of bearing / Equivalent dynamic load on bearing)a
2) Equivalent dynamic load on bearing = (XVFr + Yfa) Ka
3) L10 = (Lh10 x 60 x n) / 106

Substituting the given values we get,

Equivalent dynamic load on bearing = (XVFr + Yfa) Ka
= 6150 N

Therefore, basic dynamic capacity of bearing = L10 = (C / Pe)a
= 69448.45 N

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