Cam Roller Bearings

What is a cam roller bearing?

A cam roller bearing is a heavy-duty roller bearing with a thick outer ring that rolls directly on a cam, track, or guide rail. The outer ring is the running surface, so it can take high loads and shocks from the surface it rolls on without needing a separate wheel or housing. Cam roller bearings come in two main forms: stud types, which bolt straight into a machine frame, and yoke types, which fit onto a pin or shaft supported on both sides.

A standard cam roller bearing has four main parts:

• A thick-walled outer ring, which rolls on the cam or track
• A stud or an inner ring, which fixes the bearing to the machine
• Needle rollers or cylindrical rollers between the outer ring and the stud or inner ring
• Washers or flanges that guide the outer ring axially, and seals or shields on both sides.

The outer ring profile is one of the most important features.

• Most cam rollers have a crowned (slightly curved) outer ring, which keeps the load near the centre of the ring if the roller is tilted against the track. This reduces edge loading and wear on both the roller and the track.
• Cylindrical (flat) outer rings are also available for accurate tracks where the highest load capacity is needed.

Outer rings, studs, inner rings, and rollers are made from hardened bearing steel, and stainless steel versions are also available. Most cam roller bearings are supplied greased and ready to fit.

Why are cam roller bearings essential?

They give machines a strong, compact, and simple way to follow a cam or guide a moving part along a track. The thick, hardened outer ring carries heavy radial loads and shocks directly from the track, while the bearing inside lets it roll with low friction. Because the bearing and wheel are one part, there is nothing extra to design, machine, or assemble.

Stud types fit in a single drilled hole with a nut, which makes them quick to fit and replace. Yoke types are supported on both sides, so they carry higher loads and are better suited to heavy-duty machinery. Both come in standardised sizes, so they are easy to source and swap.

Typical applications include:

• Cam mechanisms and indexing drives
• Conveyors and transfer systems
• Forklift masts and lifting equipment
• Packaging and bottling machines
• Printing machines
• Linear guides and slides
• Steel and metal processing lines
• Automated handling and robotics
• Sliding doors and gates
• Textile and food processing machinery

The main types of cam roller bearings

• Stud type cam rollers - These have an integral threaded stud in place of an inner ring, so they bolt directly into a machine frame. They are compact and quick to fit, and are often called cam followers.
• Eccentric stud type cam rollers - These have an eccentric collar on the stud, so the roller position can be adjusted after fitting to remove play or share the load between several rollers.
• Yoke type cam rollers with axial guidance - These have an inner ring and are mounted on a pin or shaft, with washers that guide the outer ring. They carry higher loads than stud types of the same size because the pin is supported on both sides.
• Yoke type cam rollers without axial guidance - These have no washers to guide the outer ring, so the surrounding parts must provide axial guidance. Some versions are separable, so the outer ring, rollers, and inner ring can be fitted separately.
• Yoke type cam rollers without an inner ring - These run directly on a hardened and ground pin, which saves space and allows a larger pin diameter.
• Caged and full complement cam rollers - Caged types run with lower friction and suit higher speeds. Full complement types have no cage, so more rollers can be fitted, giving higher load capacity for slow or shock-loaded applications.
• Cylindrical roller cam rollers - These have one or two rows of cylindrical rollers instead of needles, and carry the highest radial loads, with some ability to take axial loads.

Material and design variants include:

• Sealed cam rollers - With contact seals for better protection in dirty or wet conditions.
• Stainless steel cam rollers - For wet, corrosive, or hygienic environments.
• Cam rollers with polymer tyres - With a plastic outer layer for quieter running and to protect soft tracks.

How to choose the right cam roller bearing?

• Stud or yoke type - Choose a stud type for quick fitting into a single hole. Choose a yoke type where loads are higher and the roller can be supported on both sides.
• Size and dimensions - Choose the outer diameter to suit the track and space available. For stud types, check the stud diameter, thread, and length. For yoke types, check the bore suits the pin.
• Load - Work out the radial load and any shocks. Compare it with the bearing’s basic dynamic load rating and basic static load rating, and with the permissible load on the outer ring and stud or pin, which are published in manufacturers’ catalogues.
• Track - The track or cam must be hard enough and smooth enough for the load. A soft track will wear or dent quickly, even if the roller itself is strong enough.
• Outer ring profile - Use a crowned outer ring where alignment between the roller and track cannot be guaranteed. Use a cylindrical outer ring where alignment is accurate.
• Caged or full complement - Caged rollers suit higher speeds. Full complement rollers suit higher loads and lower speeds.
• Environment - Use sealed types for dirt and moisture, and stainless steel for wet, corrosive, or hygienic conditions.

Essential references and specialised ranges

How the numbering works:

Cam roller numbering varies between manufacturers and types. The most common metric series are:

Stud types:

KR = single-row stud type, where the number is the outer diameter in mm, so a KR 35 has a 35mm outer diameter

KRE = stud type with eccentric collar

KRV = full complement stud type

NUKR = double-row full complement cylindrical roller stud type

Yoke types:

NATR = yoke type with axial guidance, caged needle rollers

NATV = yoke type with axial guidance, full complement needle rollers

NUTR = yoke type with full complement cylindrical rollers

STO = yoke type without axial guidance, with inner ring

RSTO = yoke type without axial guidance or inner ring

Always check the outer diameter, bore or stud diameter, thread, and width before ordering a replacement.

Suffixes:

PP = sealed version with an optimised crowned outer ring profile

X = cylindrical (flat) outer ring instead of crowned

2RS, 2RSR = contact seals on both sides

UU = sealed type

R = crowned outer ring

V = full complement rollers

Suffix codes vary between manufacturers, so check the supplier’s catalogue for the exact meaning.

FAQ - All you need to know about cam roller bearings

What is the difference between a cam roller, a cam follower, and a track roller?

The terms are often used for the same thing. Cam follower usually means a stud type, which bolts straight into a frame. Track roller and cam roller are often used for both stud types and yoke types.

What is the difference between stud type and yoke type cam rollers?

A stud type has a threaded stud built in, so it fits into a single hole and is held from one side. A yoke type has an inner ring and fits onto a pin supported on both sides, like a wheel in a fork. Because the pin is supported at both ends, yoke types carry higher loads.

Why do most cam rollers have a crowned outer ring?

A crowned outer ring has a slightly curved running surface. If the roller is tilted against the track, the load stays near the centre of the ring instead of digging in at the edges, which reduces wear on both the roller and the track.

Do cam roller bearings need lubrication?

Yes. They are supplied greased, but many applications need regular regreasing, especially with heavy loads, shocks, or dirt. Stud types are usually regreased through a grease nipple in the stud end. Yoke types are regreased through a lubrication hole in the pin or inner ring.

Click here to learn how to maintain a bearing.

Can I replace a cam roller bearing myself?

In most cases, yes. For stud types, hold the stud with a screwdriver, Allen key, or spanner while undoing the nut, then fit the new roller and tighten the nut to the torque given in the manufacturer’s catalogue. For yoke types, remove the pin, fit the new roller, and make sure it is clamped or located axially as the design requires. Never hammer on the outer ring.

How do I identify a cam roller I need to replace?

The reference is usually marked on the stud head, inner ring, or side of the outer ring. If the markings are worn away, measure the outer diameter, outer ring width, and the stud diameter and thread, or the bore for yoke types. Also note whether the outer ring is crowned or flat, and whether the bearing is sealed.

Click here to learn how to measure a bearing.

How can I tell if a cam roller is worn or failing?

Warning signs include:

• Flat spots, pitting, or flaking on the outer ring
• The roller sliding instead of rolling along the track
• Rough or uneven rotation when turned by hand
• Play between the outer ring and the stud or inner ring
• Noise or vibration as the roller passes along the track
• Grease leaking from the seals
• Wear marks or grooves forming on the track

Click here to learn how to recognise a failing bearing and tips on how to extend the life of bearings.