Question

2) Breifly discuss expected life for the journal bearings from H10 problem 2) compared to equivalent ball bearings from problem 1) above.

Answer 1

WHERE IS H10 PROBLEM ??

Bearings required to support the comparatively moving elements. Journal bearings support the cylindrical shaft and bearing measure designed supported lubricating substance and lubrication mechanisms.

Volume of wear = specific wear rate x Applied load x distance of sliding

v? = kWd

h = kPVt

Wear constant k can be considered based on the material used.

Equivalent load on ball bearings P = V X F_r + Y F_a

Where

V - Rotation factor = 1 if inner ring rotates,

V = 1.2 if outer ring rotates,

X - radial factor,

F_r - applied radial load,

Y - thrust factor,

F_a - applied thrust load.

X & Y factors depend upon bearing geometry, number of balls and size of balls. These factors are determined from tables and equivalent load is calculated based on those values. These tables contain "C0", which is static load rating. Static Load Rating C0 is defined as radial load causing permanent deflection greater than 0.01% of ball diameter. Dynamic load rating (catalogue C reading) is the load which 90% (reliability = 0.9) of a group of identical bearings will sustain for minimum of 106 cycles.