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A hub flange is a device used to support a wheel, pulley, or sprocket on a machine. Consisting of a flat steel plate with mounting bolts around the perimeter, the hub flange provides a location to mount the pulley, wheel or gear, while also providing a bearing location to allow the flange to rotate gently. It is common for the hub flange to be used as a component in a bearing assembly, making replacing a failing bearing a simple one-step procedure.
The purpose of a hub flange is not only to house the mounting studs for the wheel, pulley, or sprocket, but also to provide a flat, smooth surface that is machined perfectly plumb to provide a direct running accessory that fits. correctly. By creating the perfectly flat and vertical flange, the wheel or sprocket will not wobble or rotate off center when mounted to the hub assembly. This increases efficiency and greatly increases the life expectancy of the bearing as a whole. In the case of a belt or chain, these components also come to life by entering the assembly directly and do not experience premature wear from rubbing against the side of an unstable assembly.
To create a hub flange that is part of a bearing assembly, the flange is usually cast or machined as an inner or outer bearing race, depending on the application. This type of manufacturing design, popular in automotive and machine design and manufacturing, greatly increases the overall strength of the flange assembly and reduces the cost of manufacturing the assembly. This cost savings can be passed on to the customer, making the design popular with discount auto supply stores as well as auto and machine manufacturers.
While some hub flange designs use a greaseable bearing hub, the vast majority do not. The sealed bearing used in the non-greasable design allows the unit to run for long periods without maintenance. The downside to this type of assembly is that once a problem with the drive is detected, the entire assembly must be replaced. With a greaseable unit, the bearing is lubricated before and during each work cycle. Not only does this provide the proper amount of lubrication for a long hub flange life, but it also forces the worker to look at the assembly and check for problems at every start-up.