Tapered Roller Bearings: What You Need to Know

Many types of bearings are on the market today, each specific to your needs and wants.

Tapered roller bearings are rolling element bearings that can support and manage axial and radial forces—one of the industry's most versatile bearings being a tapered cup and tapered cone.

We at Bearing Manufacturing Company are committed to being a world-class provider for all your manufactured ball and roller bearing products. 

We thought it would be advantageous to create a series of posts that included the main roller bearings types you may need for your projects. This is the third post of the five-part series. 

In case you missed it, here are the first and second articles—What are Cylindrical Roller Bearings and How are They Used? and Spherical Roller Bearings Reduce Friction and Allow Smoother Rotation.

What Are Tapered Roller Bearings?

Tapered roller bearings are rolling element bearings that can support axial forces (i.e., suitable thrust bearings) and radial forces.

The inner and outer ring raceways are segments of cones, and the rollers are tapered so that the conical surfaces of the raceways, and the roller axes if projected, would all meet at a common point on the central axis of the bearing. This geometry makes the motion of the cones remain coaxial, with no sliding motion between the raceways and the outside diameter of the rollers.  source

Advantages

• Minimize friction causing reduced heat being generated
• It can easily support directional loading
• The ability to support heavy thrust and radial loads beats spherical, cylindrical, or needle roller bearings.
• Most can support pure radial, pure axial, or any combination without modification.
• Have a high load capacity
• Proper rolling motion, meaning less skidding or sliding when unloading
• Minimal load requirements source

Disadvantages

Like most things, choosing a tapered roller bearing also has disadvantages. 

When misalignment occurs, the results can cause irreversible damage. If you know the cause for misalignment is high, choosing a different option, such as spherical roller bearings, would be a good idea. 

A second considerable disadvantage with tapered roller bearings is speed. They are suited for higher-speed operations, which may cause concern depending on the operation. source

What applications are tapered roller bearings used for?

• Vehicle wheel bearings while working continually with radial and axial forces 
• Suitable for moderate-speed, heavy-duty applications requiring durability
• Automotive wheel bearings 
• Agriculture machinery shafts 
• Aircraft fuel pumps 
• Engines and reducers 
• Railroad axles
• Mining
• Construction
• and more…

Earlier bearing designs tended to fail because of friction and heat generated, a problem that tapered roller bearings are designed to solve. Through their tapered shape, the bearings can transfer loads evenly.

The construction is designed to handle combination loads, such as axial and radial loads in tandem.

As the projected lines of the raceway meet at a common point, the bearing axis improves rolling while reducing friction. 

It can increase or decrease load capacity depending on the contact angle. The greater the slope, the greater the contact angle. 

They are used in pairs for better radial load handling, while in some heavy-duty applications, two or four rows are combined into a single unit. source

The combined tapered roller bearings simultaneously support both the radial and the axial load (in both directions) and, by maintaining the correct interlocking of gears, transmit a large amount of driving force to the wheels on both sides.

Components of tapered roller bearings:

• Cup and Cone- The cup includes the outer ring in which the bearings ride. The non-separable cone assembly consists of the inner ring, rollers, and cage. In the raceways where the rollers operate, there is an angle corresponding to the rollers' taper. The inner raceway is called a cone, while the outer raceway is called a cup. The cage, also known as a retainer, separates the rollers, ensuring even load distribution and smooth rotation. The angled surfaces of the rollers, cones, and cups actively align them; the cage mainly serves to evenly space the rollers and hold them together. 

• Rollers (Axial And Radial Loads)-Tapered cylindrical rollers are used in these bearings. The contact angle and number of rows determine the load type and capacity of the bearing. The number of rollers on a bearing can increase its load-bearing capacity.
  
  
• Cages- Different than the cages in other bearing types, the most common type of cage is the pin cage. As part of the inner core assembly, the cage helps distribute the roller units. 
  
  
• Lubrication- helps reduce friction, noise, heat, etc., between rollers and raceways. Several lubricants are used, including synthetic oil, petroleum-based oil, silicone-based oil, greases, dry films, etc.
  
• Seals- effectively prevent the bearing from impeding by environmental contaminants and moisture. Impurities may affect the proper functioning of the bearing. 

Standards

Tapered roller bearings must comply with the standards outlined for the roller bearing.

A compilation of specific industrial standards has been developed:

• ISO10317 -- Tapered roller bearings designation system
• ISO 355 -- Tapered roller bearings dimensions and boundaries
• ABMA STD 19.1 -- American Bearing Manufacturers Association specifications for tapered bearings source

Why choose this bearing over another?

The design characteristics of tapered roller bearings set them apart from other types of roller bearings. There are two different sizes of diameters on the ends of the rollers, thus the name "tapered rollers."

Rolling raceways have an angled surface that corresponds with the taper of the rollers, making these rings look like cone segments; the inner raceway is called a cone, while the outer raceway is called a cup.

A cage commonly referred to as a retainer separates the rollers and keeps them a fixed distance apart, ensuring a smooth rotation and even distribution of load.

The angled surfaces of the rollers, cones, and cups actively align them, so the cage primarily serves to evenly space the rollers and contain them within the assembled assembly.

A flange prevents the roller and cage assembly from leaving the raceway at high speeds. 

According to theory, if the tapered rollers, cones, and cups were geometric cones, their apexes would meet at the same point on the central axis of the bearing. source

Need a bearing that works with radial and axial forces?

Need to reduce friction and reduce heat generated?

Need a bearing that can handle heavy-duty operations?

Maintenance 

We know how costly downtime can be. We're here to help.

With the bearing repair services to meet your needs, you won't have to look any further. 

Bearing repair services reduce downtime and lead time, save money and increase bearing life. 

Closing thoughts

Tapered Roller Bearings are designed to reduce friction and, in turn, reduce the heat that can cause bearing structures to fail. 

This bearing is used in many industrial applications and is optimal for those undergoing excess loads.

At BMC, we have the services to help you get the bearings you need, including modification, manufacturing, and repair. 

Talk to one of our bearing experts to allow us to help you get started. 

p.s. Stay tuned for our Needle Roller Bearings post next. Needle bearings can be made with or without a cage; if they have a cage, they can tolerate very high speed, but if not, they can support significant radial or axial load.