Tuesday, October 26, 2010 03:32
What's a roller bearing? What’s a plain bearing? Bearing or bushing? Why do you care? The last time someone asked you a technical question and you didn’t even have a clue, why not get one? Here’s a bit of knowin’ for you to carry about with you.
The bearing is a pretty essential automotive mechanism. What part allows engine and driveline parts to rotate with minimal friction? Imagine something consequential like an axle hub without a functioning bearing.
Any time two moving parts intersect, if there’s a separate piece of material that spans their gap and bears the friction of their interrelated movement, basically put, that’s a bushing or a bearing. A bushing doesn’t have any moving parts; it’s a material in place to ease the movement of the parts it supports, like the banana peel on the ground when you fall on your ass, if the peel was a brass fitting and your foot and the sidewalk were a block and crankshaft. Yeah, I said it.
Bearings are essentially a set of tightly fitted collars or rings (usually called “races”) with spherical or cylindrical elements between the collars. The round elements – the cylinders or balls – support the rotating motion of one part against another within the races.
A ball in the bearing makes it a ball bearing (the ball is a ball, made of whatever material necessary for the application, not a “ball bearing”). Ball bearings can’t handle as much load as a roller bearing (described next) but are more tolerable of misaligned rotation-loads, they create less friction when loaded within tolerance, and their inexpensive manufacture makes them the most common bearing.
Roller bearings function similar to a ball bearing, but with a cylindrical rotating element instead of a ball. Roller bearings cope better with increased loads, but there’s more friction. There are many variations of the typical roller bearing – needle bearings, tapered and spherical roller bearings. Roller bearings are the oldest kind of bearing – the encyclopedia told me so.