Basic Information On How Ball Bearings Work

Blog | August 14th, 2015

Friction is incurred when two separate parts make contact and slide against each other. The job of a ball bearing is to neutralize the friction generated by this rubbing action and therefore remove the heat produced by high-speed contact. In olden times, when a vendor was taking produce to market, he’d rub a little meat grease into the mechanism where the wagon wheel and the cart were rubbing, and all was well. Unfortunately, modern mechanisms, ones that rely on radial movement, need a more potent solution to this age-old friction dilemma, which is why ball bearings are such an integral part of all machinery.

The Twofold Secret to Ball Bearing Success

Engineers understand friction. They’ve used this understanding to design components that can withstand thousands of revolutions per second without the intersecting point between a rotating shaft and a physically connected static assembly exploding into a smoky, heat-savaged ruin. The moving and non-moving sections are in contact, with the shaft exhibiting a blur of radial motion, but a third component is acting as a friction-killing bridge between them. This force-spanning ball bearing assembly is using a series of small rolling balls as an intermediary agent. The balls cancel friction and heat by drawing on two key features. Firstly, the balls surround the moving part as a ring, but this circle requires very little contact, thus leaving gaps. This minimal contact approach goes some way to answering the problem because the rubbing action no longer happens as a result of both surfaces being fully locked together.

The second and most important part of the design comes from the design of the actual balls. Each one is engineered to roll smoothly between two rings. They’re polished to a high sheen and made of dense, load-bearing steel or some other alloy that demonstrates uniform surface characteristics. The surface of each spherical element rolls in any direction while delivering fluid motion. Finally, there’s a third influential ingredient that ties these two physical components together. A lubricant is working in concert with the low surface contact feature and the ring of hardened metal spheres to maximize friction-free radial momentum.

A Ring to Rule the Mechanical Integrity of the Bearing

The uniformity of the rolling spheres and the lubricating properties of oil or grease take on the role of the workhorse components in this configuration, but we still require physical integrity, a housing that can cope with the in-motion mechanism and the static assembly. A series of concentric rings fill this purpose. An inner ring, for example, form fits against a shaft. Meanwhile, a second ring is fitted as a rim. The balls are sandwiched between the rings and fixed in place by a cage or rail structure. This final component traps the balls between the rings but does not hamper the rotational characteristics of the spheres.

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