Bearings for Crushers and Mining Equipment

The toughest job a bearing can do

Few machines punish bearings like crushers and mining equipment. A jaw crusher hits rock with enormous force on every stroke. A vibrating screen shakes its bearings thousands of times a minute. Conveyors and mills run day and night in clouds of abrasive dust, with water and mud never far away.

In a quarry or mine, one failed bearing can stop a whole processing line. Large crusher bearings are expensive, often hard to source quickly, and slow to replace. That is why choosing the right bearing, sealing it properly and looking after it pays back many times over.

This guide explains what mining duty demands, which bearings each machine uses, how to seal and lubricate them, and how to spot trouble early.

What mining and crushing demand from bearings

• Shock loads: every time a crusher bites rock, the bearings take a sudden peak load far above the average. Bearings must be rated for shock, not just steady load.

• Very heavy loads: crusher shafts, mill trunnions and conveyor pulleys carry tonnes. Roller bearings, usually spherical roller bearings, are the default.

• Vibration: vibrating screens and feeders deliberately shake their bearings at high acceleration. Standard bearings wear out fast under this.

• Abrasive dust: rock and ore dust is extremely abrasive. Once it gets inside a bearing, it grinds the raceways and rollers.

• Water and slurry: dust suppression sprays, rain, wet ore and washing plants all bring water close to the bearings.

• Shaft bending and misalignment: long, heavily loaded shafts and flexing steel frames mean bearings must tolerate misalignment.

• Heat: high loads and churned grease raise bearing temperatures, which shortens lubricant life.

• Remote sites: mines and quarries are often far from suppliers, so downtime waiting for a bearing is costly.

Bearings by machine

Machine	Bearing positions	Typical bearings
Jaw crusher	Two outer bearings carry the eccentric shaft in the frame; two inner "pitman" bearings carry the moving jaw	Large spherical roller bearings (Timken)
Cone and gyratory crusher	Radial bearings and thrust bearings around the main shaft and eccentric	Special cylindrical roller bearings, tapered and cylindrical thrust bearings, plain bronze bushings (Timken)
Impact crusher (HSI, VSI) and hammer mill	Rotor or impactor shaft, both sides	Spherical roller bearings in solid or split pillow block housings
Vibrating screen	Exciter shaft bearings	Vibrating-screen grade spherical roller bearings, or cylindrical roller bearings
Vibrating feeder	Exciter or drive shaft	Vibratory-grade spherical roller bearings
Belt conveyor	Head, tail and bend pulleys; take-ups; idler rollers	Spherical roller bearings in plummer blocks; deep groove ball bearings in idlers
Ball, rod and SAG mills	Trunnions, pinion shaft, gearbox	Large plain (hydrodynamic) trunnion bearings or spherical roller bearings; spherical or cylindrical roller bearings on the pinion
Pumps (slurry, dewatering)	Pump shaft	Tapered, cylindrical and angular contact bearings in bearing frames
Mining trucks, loaders, excavators	Wheels, axles, slewing rings	Tapered roller bearings, slewing ring bearings

For conveyor bearings in more detail, see spherical roller bearings for conveyor systems and take-up bearings for belt conveyors.

Key bearing types for mining duty

Spherical roller bearings

The workhorse of crushing and mining. Two rows of barrel-shaped rollers carry heavy radial loads and some axial load, and the bearing self-aligns, so it copes with shaft bending and frame flex. Jaw crushers, impact crushers, conveyor pulleys and many mills rely on them.

• Tapered bore versions (suffix K) mount on adapter or withdrawal sleeves, making fitting and removal on large shafts much easier.

• Larger internal clearance (C3 or C4) is common, to allow for heat and heavy interference fits.

• Steel or brass cages stand up to shock better than polymer cages.

Vibrating screen bearings

Vibrating screens need spherical roller bearings built specially for vibration. These have tighter manufacturing tolerances, larger radial internal clearance and a rugged cage. One maker's vibratory-grade range is designed for vibration above 5 g and runs cooler, which extends grease life (Bearing King). Variants with a coated bore resist fretting on the shaft.

Fitting a standard spherical roller bearing to a vibrating screen is a common cause of early failure. Check that replacements are a vibratory grade.

Cylindrical roller bearings

They carry very high radial loads and allow the shaft to float axially. They are used in cone crushers, vibrating screen exciters, mill pinions and gearboxes.

Tapered roller bearings

They take combined radial and heavy axial loads. They are used in cone crusher thrust positions, mining truck wheels and gearboxes.

Plain bearings and bushings

Bronze or composite bushings carry the eccentric and main shaft in many cone and gyratory crushers. Large mill trunnions often run on oil-film plain bearings.

Housings

Most spherical roller bearings in mining run in split plummer blocks or solid pillow block housings. Split housings let you change the bearing without removing the shaft. Choose housings with the right seals for the dust and water present.

Sealing and lubrication

Seals for dust and water

Contamination is the biggest killer of mining bearings. Abrasive dust leaves a frosty grey worn surface, and hard particles dent the raceways, which leads to flaking (Timken).

Seal type	How it works	Best for
Lip (contact) seals	Rubber lip runs on the shaft	Moderate dust, low to medium speed
Labyrinth seals	Winding path, often filled with grease	Heavy dust, higher speeds
Taconite seals	Labyrinth plus lip seal, grease-purged	The worst dust and slurry, such as crushers and conveyors in mines
V-rings and end covers	Extra outer barrier	Added protection on exposed housings

Grease-filled labyrinth and taconite seals work best when they are purged regularly: fresh grease pushes dirt outward before it can get in.

Lubrication

Poor lubrication is one of the leading causes of crusher bearing failure (Timken).

• Use the grease or oil the machine maker specifies, usually a heavy-duty, extreme-pressure (EP) grease for shock-loaded bearings.

• Keep oil viscosity at or above the minimum the maker recommends at operating temperature.

• Relubricate on schedule. In dusty or wet sites, more frequent small top-ups help purge contamination.

• Don't over-grease. Too much grease churns, overheats and breaks down.

• Never mix grease types.

• Automatic lubricators save labour and give steady, regular greasing on remote or hard-to-reach bearings.

See the types of grease available for general options, but always follow the equipment maker's specification.

Installation, condition monitoring and failure signs

Installation

• Check shaft and housing fits. Fits that are too tight or too loose cause creep, vibration and early failure. Reused shafts wear undersize and housings go out of round, so measure them every time a bearing is changed (Timken).

• Set the clearance on tapered bores. When driving a tapered-bore bearing up its sleeve, measure the reduction in internal clearance with feeler gauges and stop at the maker's value.

• Heat, don't hammer. Use an induction heater to fit bearings on shafts. Hammering damages raceways.

• Align the shaft. Check alignment of motor, coupling and shaft after installation.

• Find the root cause. When a bearing fails, inspect it carefully before throwing it away; the damage pattern shows whether the cause was dirt, lubrication, fit or overload.

Condition monitoring

• Measure vibration on crushers, screens and conveyor drives at regular intervals.

• Check bearing temperature with an infrared gun or fitted sensors.

• Listen for changes in sound with an ultrasonic or mechanical stethoscope.

• Sample oil on oil-lubricated bearings for wear metals and dirt.

• Keep records, so rising trends are spotted early.

Warning signs

• Rising temperature on a housing compared with its neighbour or its normal reading

• New noise: rumbling, grinding or knocking

• Higher vibration, especially on screens and crushers

• Grease leaking out dark, dry or full of grit

• Rust or fretting marks on the shaft or in the bore

• Shaft movement or wobble in the housing

Plan replacements during scheduled shutdowns, and keep critical spares such as crusher, screen and head pulley bearings in stock on remote sites.

Keeping crushers and mines running

Mining bearings face shock, heavy loads, vibration and abrasive dust all at once. Use spherical roller bearings with the right clearance on crushers and conveyors, vibratory-grade bearings on screens, and the specified roller and plain bearings on cone crushers. Then protect them with good seals, regular lubrication, correct fits and condition monitoring.

When ordering, give your bearing supplier the bearing number, the machine make and model, the position, and whether it needs a vibratory grade, tapered bore, special clearance or housing. For remote sites, ask about holding critical spares in stock.

Frequently asked questions

1. What bearings are used in a jaw crusher?

Jaw crushers use large spherical roller bearings. Two outer bearings support the eccentric shaft in the crusher frame, and two inner "pitman" bearings support the moving jaw. They are chosen for heavy shock loads and their ability to self-align.

2. What bearings are used in cone crushers?

Cone and gyratory crushers usually combine special cylindrical roller bearings for radial loads with tapered and cylindrical thrust bearings for axial loads. Many also use bronze or composite plain bushings around the eccentric and main shaft. Exact bearings depend on the crusher model.

3. What is a vibrating screen bearing?

It is a spherical roller bearing made specially for vibrating screens, with tighter tolerances, larger internal clearance and a stronger cage. It handles high vibration and runs cooler than a standard bearing. Using a standard bearing on a screen often leads to early failure.

4. Why do crusher bearings fail early?

The most common causes are dust and dirt getting past the seals, poor or wrong lubrication, and incorrect shaft or housing fits. Shock overload, misalignment and fitting the wrong bearing grade also shorten life.

5. How often should crusher bearings be greased?

Follow the crusher maker's relubrication schedule. In very dusty or wet conditions, smaller and more frequent top-ups help purge contamination from the seals. Avoid over-greasing, which causes heat, and never mix grease types.

6. What clearance should mining bearings have?

Many crusher, screen and heavy conveyor bearings use C3 or C4 internal clearance, to allow for heat and tight shaft fits. Always use the clearance class specified by the equipment maker, especially for vibrating screens.