TABLE OF CONTENTS The function of bearings is to keep the shaft or rotor properly aligned with the stationary parts under axial and radial loads. Bearings that provide radial positioning to rotors are known as line or radial bearings. Bearings that position the rotor axially are called thrust bearings. Thrust bearings usually serve as thrust and radial bearings.
The main types of bearings are journal and rolling-contact (ball and roller) bearings. The ball and roller bearings are also known as antifriction bearings. The most common bearings used on centrifugal pumps are the various types of ball bearings. Roller bearings are used less often. However, spherical roller bearings are used frequently for large shaft sizes, for which there is a limited choice of ball bearings.
In horizontal pumps with bearings on each end, inboard bearings are located between the casing and the coupling. The bearing on the outside is the outboard.
The bearings are usually mounted in a housing supported by brackets which are attached or integral to the pump casing. The lubricant is usually contained within the housing. The bearings must be kept within proper temperature limits due to the heat generated within the bearings. For bearings that are provided with a forced-feed lubrication system, cooling is achieved by circulating the oil through a separate water-to-oil cooler. Otherwise, cooling liquid enters a jacket located inside the housing to remove the heat.
There are rigid and self-aligning bearings. A self-aligning bearing will adjust itself automatically to a...
