Spherical Roller Thrust Bearings
195 products
Loading filters…
Spherical Roller Thrust Bearings
What is a spherical roller thrust bearing?
A spherical roller thrust bearing is a self-aligning rolling bearing designed to carry very heavy axial loads, together with a moderate radial load. It uses asymmetrical barrel-shaped rollers set at an angle to the bearing axis. The housing washer has a raceway shaped like part of a sphere, so the shaft washer, rollers, and cage can tilt within it, which lets the bearing adjust to misalignment and shaft deflection.
A standard bearing has four main parts:
- A shaft washer, which fits onto the shaft and rotates with it
- A housing washer with a spherical raceway, which sits in the housing
- A single row of asymmetrical barrel-shaped rollers
- A cage that keeps the rollers evenly spaced.
Because the rollers are set at an angle, the load passes through the bearing at an angle to the shaft.
- This is what allows the bearing to carry radial load as well as axial load.
- A flange on the shaft washer guides the rollers and keeps them in position.
The shaft washer, rollers, and cage are held together as one unit, while the housing washer is separate and can be fitted on its own. Washers and rollers are usually made from hardened chrome steel (grade 52100). Cages are most commonly pressed steel or machined brass.
Why are spherical roller thrust bearings essential?
They carry the heaviest axial loads of any common thrust bearing type, while also taking radial load and adjusting to misalignment. This means a single bearing can do a job that would otherwise need a thrust bearing, a radial bearing, and very accurate alignment. They carry axial loads in one direction only. Any radial load acting at the same time must stay within a limit set by the manufacturer, which is usually a proportion of the axial load.
They can also run at relatively high speeds for a roller thrust bearing, and they handle shock loads well. Their boundary dimensions are standardised internationally. So a bearing of a given reference has the same bore, outer diameter, and height, regardless of which reputable manufacturer makes it.
Typical applications include:
- Hydroelectric turbines and generators
- Marine propeller shafts and thrusters
- Plastic and rubber extruders
- Crane hooks and swivels
- Vertical pumps
- Mixers and agitators
- Heavy-duty gearboxes
- Paper machine refiners and pulpers
- Oil drilling swivels
- Rolling mill equipment
The main types of spherical roller thrust bearings
- 292 series - The lightest section, with a small cross section that suits higher speeds and limited space.
- 293 series - A medium section with larger rollers and a higher load capacity for the same bore.
- 294 series - The heaviest section, with the highest load capacity, used for the most heavily loaded applications.
- Basic design - The original design, usually fitted with a machined brass cage.
- High-capacity designs (E) - These have larger rollers and an optimised internal design, giving a higher load capacity than the basic design of the same size. Smaller sizes usually have a pressed steel cage and larger sizes a machined metal cage.
- Double-direction arrangements - Two bearings are fitted against each other so axial loads can be taken in both directions. Springs are often used to keep a minimum load on the unloaded bearing.
Cage variants include:
- Pressed steel cages - Strong, cost-effective, and standard on many smaller high-capacity bearings.
- Machined brass cages - Very robust, suited to high temperatures, shock loads, and heavy duty, and standard on many larger sizes.
How to choose the right spherical roller thrust bearing?
- Size and dimensions - The bore must suit the shaft; the outer diameter and height must fit the housing. For the same bore, a heavier series has a larger outer diameter, larger rollers, and higher load capacity, but takes up more space.
- Load - Work out the axial and radial loads and whether they are steady or involve shocks. Compare them with the bearing’s basic dynamic load rating and basic static load rating, which are published in manufacturers’ catalogues. Check that the radial load stays within the manufacturer’s limit for the axial load acting at the same time.
- Minimum load - These bearings need a minimum axial load at all times to stop the rollers skidding, which damages the raceways. This is particularly important at higher speeds, in vertical arrangements, or where the load can reverse, and springs are often used to keep the bearing loaded.
- Misalignment - These bearings adjust to misalignment and shaft deflection, but the permitted angle depends on the series, size, and load. Check the manufacturer’s catalogue if misalignment is significant.
- Lubrication - Oil lubrication is generally recommended, as it carries heat away and reaches the roller ends and flange properly. Grease can be used at low speeds.
- Cage - Pressed steel cages suit most general applications. Machined brass cages are better for high temperatures, shock loads, and heavy duty.
Essential references and specialised ranges
How the numbering works:
The first two digits, 29. Identifies a spherical roller thrust bearing.
The third digit indicates the series: 292 is the light series, 293 is medium, and 294 is heavy.
The last two digits indicate the bore:
Multiply by five (for example, 29412 = 60mm and 29320 = 100mm)
For bores of 500mm and above, the bore is written in full after a slash, so a 292/500 has a 500mm bore.
Suffixes:
No suffix = basic design, usually with a machined brass cage
E = high-capacity design with larger rollers
E1 = high-capacity design
EM = high-capacity design with a machined brass cage
MB = machined brass cage
VU029 = modified shaft washer for small axial clearance
Spherical roller thrust bearings do not have internal clearance classes like C3, as their axial position is set by how they are mounted.
Suffix codes vary between manufacturers, so check the supplier’s catalogue for the exact meaning.
FAQ - All you need to know about spherical roller thrust bearings
What is the difference between a spherical roller thrust bearing and a cylindrical roller thrust bearing?
A cylindrical roller thrust bearing carries axial load only and cannot tolerate misalignment. A spherical roller thrust bearing carries axial load together with some radial load, adjusts to misalignment, and can usually run faster.
Can they take radial loads?
Yes, but only alongside an axial load. The radial load must stay within the manufacturer’s limit for the axial load acting at the same time. For larger radial loads, a separate radial bearing is needed.
Can they tolerate misalignment?
Yes. The spherical raceway in the housing washer lets the bearing adjust to misalignment and shaft deflection. The amount allowed depends on the series, size, and load, so check the manufacturer’s catalogue.
Do spherical roller thrust bearings need lubrication?
Yes, lubrication separates the rollers from the raceways and flange, reduces friction, and protects against corrosion. Oil is generally recommended, particularly at higher speeds, as it also carries heat away from the bearing. In vertical shafts, the bearing should sit fully in the oil bath or receive a steady oil feed.
Click here to learn how to maintain a bearing.
Can I replace a spherical roller thrust bearing myself?
In many cases, yes. The shaft washer, rollers, and cage are fitted onto the shaft as one unit, and the housing washer is fitted into the housing separately. Larger shaft washers are usually heated with an induction heater so they expand onto the shaft. Make sure the housing washer is fully supported, and never strike the bearing directly with a hammer, as this can damage the washers and rollers.
How do I identify a bearing I need to replace?
The reference is usually marked on the side face of the washers. If the markings are worn away, measure the bore, outer diameter, and overall height with callipers and match them against a size chart. Also note the cage material and whether it is pressed steel or machined brass.
Click here to learn how to measure a bearing.
How can I tell if a bearing is worn or failing?
Warning signs include:
- Grinding, rumbling, or clicking noises
- Increased vibration
- Rough or uneven rotation
- Increased axial play in the shaft
- Overheating
- Discoloured or contaminated lubricant
