Ordinary ball bearings aren’t up to the task alone. That’s why you see tapered roller bearings in heavy equipment, gearbox shafts, and wheel hubs where they needs to carry axial thrust as well as radial weight. Manufacturers has translated that ability into usable sizes which appears in the size chart above. Match a bearing to your housing and shaft without guessing.
Once you lay this out in geometry, the reason for all this is simple. Both raceways are angled to match the taper of each roller, this means that as they roll, they’re pointed at a common imaginary point. This creates line contact instead of point contact spreading the load and reducing friction. The chart is broken down into each component of assembly to show what each dimension actualy accomplishes.
How Tapered Roller Bearings Work
The shaft holds inner cone. The housing holds the outer cup which presses against the cone. The rollers transfer force, and the cage hold them evenly spaced apart. Because they’ll act differently under load if any of these components are changed you need to maintain alignment of these component.
And there’s another consideration: What are the combined loads from both of these applications? How big is your space? For example, narrow series are used where there isn’t much space like inside a gearbox. Heavier, wider series can handles extreme force, such as on a rolling mill or mining crusher. The chart below presents width, bore, and outside diameter together. This lets you quickly compare the family that’ll clear your housing while also carrying the necessary thrust.
The low-key choice between axial capacity and radial stiffness? Contact angle. If it’s fairly steep, the bearing will accommodates more end thrust but sacrifice some radial rigidity. If it’s shallow, it’ll resist deflection of the shaft (preventing excessive side load). In the real world, most applications is somewhere in the mid-range where each quality are needed about equally. You read ’em in the chart; decide which way to lean your own design before you should of order bearings.
Heat or noise are often symptoms of something you did wrong during installation, not an immediate failure. It’s also important to keep both the housing and shaft clean and within the allowed limits so that rings don’t move and tear up seating surface. Paired bearing preload is another factor. If there’s not enough, the rollers skid and if there’s too much they can overheats. Use a feeler gauge or torque wrench to set the preload to match the chart’s values for your finished dimensions.
For maintenance, it’s simply about checking things like lubrication condition, vibration and of course temperature regularily. Contaminated grease and wrong preload will show up as a hot running housing far ahead than any visual damage being present. Slow fretting due to a loose ring under load is prevented by checking housing and shaft fits each time you do an overhaul.
What’s most valuable about a size chart is that it consolidates all these individual decisions into a single coordinated one. Once you have decided on the size needed to last, determined how much room is available, and known the direction the load needs to be pushed, the size chart lets you figure out not only what might fit but what would work.
