Ball bearings in use today are highly engineered, complex devices. Without them, there wouldn't be any car motors, children's bikes, inline skates, and lawn mowers with spinning blades or ceiling fans. Bearings are made of multiple parts including an inner and outer ring, called races, and multiple ball bearings or rollers held in place in between the races. In most case, the bearing is "sealed" with some type of facing material to keep the lubrication in and contaminating elements out. Bearings made of high strength metal can carry very large loads and turn at high speeds with little friction.
When bearings work as planned, things go well, but when a bearing "goes bad," bad things happen. When your car motor starts making a loud "clunking" sound, big dollar signs soon follow. If your lawn mower starts to make a "screeching" sound, it won't be long before it makes a trip to the repair shop. When your garbage disposal sounds like it's chewing up knives and forks when all that's in it is some tossed out vegetable soup, the plumber will soon be showing up.
Bearings fail in a few simple ways, and in this Part I of this e-zine on bearings, we cover what happens to a ball bearing due to a lack of lubrication. Part II of our e-zine on bearings will cover what happens when the bearing element itself fails.
When bearings run out of lubrication, friction builds up. The friction generates heat and the heat causes the metal parts to expand. Since the outer race is generally constrained in some way and the inner race is generally filled with something like a shaft, this expansion squeezes the ball bearings so much that they can't roll. Given enough time and enough heat, they will "freeze up" and stop turning. The heat is often so high that the metal parts actually weld solidly together. Routine maintenance and adherence to manufacturer's instructions can usually help you avoid this problem. However, sometimes other factors influence lubrication loss, and you will need one of the engineers from The Warren Group to assess your loss.
Don't forget to read Part II of our e-zine on bearings where we cover what happens when the bearing itself fails.