Bearing preload increases which characteristic in rotating equipment?

Bearing preload increases which characteristic in rotating equipment?

• A. Lubrication.
• B. Weight.
• C. Electrical resistance.
• D. Stiffness.

Answer: (D)

Bearings with preload act as a stiffer support structure in a rotating system. By applying axial preload, the rolling elements stay in constant contact with the races, eliminating internal clearance. This increases the bearing’s contact stiffness, which raises the overall stiffness of the rotor-bearing assembly. With higher stiffness, deflections under load are smaller and natural frequencies are higher, improving stability and reducing certain vibration tendencies. Lubrication, weight, and electrical resistance aren’t directly increased by preload—the lubrication behavior depends on clearance and film formation, weight is fixed by the components, and electrical resistance is a material/geometry property, not a preload effect.

Bearings with preload act as a stiffer support structure in a rotating system. By applying axial preload, the rolling elements stay in constant contact with the races, eliminating internal clearance. This increases the bearing’s contact stiffness, which raises the overall stiffness of the rotor-bearing assembly. With higher stiffness, deflections under load are smaller and natural frequencies are higher, improving stability and reducing certain vibration tendencies. Lubrication, weight, and electrical resistance aren’t directly increased by preload—the lubrication behavior depends on clearance and film formation, weight is fixed by the components, and electrical resistance is a material/geometry property, not a preload effect.