Common Causes and Remedies for Roller Bearing Overheating

Blog | May 15th, 2019

This post is intended as a guide to roller bearing overheating causes. One easy enough causative factor to spot would be a low lubrication level. There’s no oily film between the rollers, so the fast-moving bearing components generate heat as they rub against one another. It’s a pity that every overheating gremlin can’t be picked up and remedied so easily. That, of course, is simply not the case.
Lubricant-Starved Overheating

Consider a situation reinterpretation. It’s true that roller bearings shouldn’t generate excessive quantities of thermal energy. The heat will discolour the metal and reduce its life expectancy. Bearing integrity goes out of the window as the high-temperatures boil of the last of the lubricant. Heat cracks are imminent, and a complete bearing failure won’t be far behind. Refocusing the fault-diagnosing strategy, the maintenance technician sees the waves of heat as a clue. The first thing to check is the oily medium. Is the lubricant level high enough? If this is an oil-submerged device, sealed inside its housing, its grease-packed inner chamber could be running dry. Alternatively, there’s a clogged oil line. It needs to be cleared of gunk before the roller bearing self-destructs.
Tracing Thermal Faults To Their Origin Point

Using an infra-red inspection tool, a repair worker can “see” heat rising off a bearing housing. It is cherry red and still getting hotter. The oil level is dropping, but that’s only because the lube is vaporizing. There’s a deeper underlying problem here, one that needs to be traced before the damage becomes irreversible. A bent shaft is one possibility. The bend changes the path of the rolling elements, so the device experiences unusual angular stress. Misalignment errors are another common cause of bearing overheating, and then there are excessive loads to consider, too. The heat is either being caused by a bearing fault, and low lubricant faults are common, or there’s an external issue to blame, in which case the indirectly applied stress factor needs to be tracked down.

Remedy the above issues, quickly and effectively. If the oil line is blocked, replace a filter and unclog the line. If an oil or grease level is low inside a sealed housing, adjust a maintenance schedule so that the levels are topped up regularly. As far as the indirect causative factors go, well, there’s no other option, is there? The repair team will have to discover the source of the bearing stress. A bent shaft or misalignment angle, excess load or strange transient weight episode, the rod transmitted excess energies need to be tracked down before they produce enough of that nasty overheating effect to cause permanent roller bearing damage.

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