How does misalignment impact bearing life in mechanical drives?

• A. Increases lubrication life
• B. Reduces load on bearings
• C. Increases bending and radial loads on bearings, reducing life
• D. Has no effect on bearing life

Answer: (C)

Misalignment introduces a bending moment on the bearing as the shaft runs off-center, so the bearing experiences not just the nominal radial load but an added moment that increases the overall load. That higher, nonuniform load raises contact stresses and accelerates fatigue in the races and rolling elements, which shortens bearing life. In life calculations, the dynamic load P climbs with misalignment, and since bearing life often scales with (C/P)^3, even a modest increase in P can dramatically reduce life. Lubrication life isn’t gained from misalignment—it's governed by factors like speed, viscosity, and film formation—so misalignment doesn’t improve lubrication. And misalignment does have a real effect on life, not zero impact, because the extra bending and radial loads accelerate wear and fatigue.