Roller bearings are rolling bearings in which cylindrical, tapered or needle shaped rollers roll as rolling elements between the inner ring and the outer ring. In contrast to the ball bearing, this creates line contact between rolling element and raceway – which allows significantly higher radial loads in a compact design and makes roller bearings the first choice for heavily loaded bearing arrangements.
Design and function of a roller bearing
Like all rolling bearings, a roller bearing consists of four basic components: inner ring, outer ring, rolling elements (here: rollers) and a cage, which keeps the rollers evenly spaced. The special feature lies in the roller geometry: thanks to line contact, the load is distributed over a larger area than in a ball bearing – this reduces the Hertzian contact stress and considerably increases the static and dynamic load capacity.
Overview of roller bearing types
Cylindrical roller bearing
Cylindrical rollers run parallel to the bearing axis. They carry very high radial loads, but are only suitable for axial loads to a limited extent. Typical applications are gearboxes, electric motors and machine tool main spindles.
Tapered roller bearing
Tapered rollers run on conical raceways. They can carry both high radial and high axial loads and are installed in pairs to absorb forces in both directions. Used, for example, in vehicle gearboxes, wheel bearings and machine tools.
Needle roller bearing
Needle roller bearings use very thin, long rollers (needles). This allows a high load capacity with an extremely low section height – ideal for confined installation conditions such as planetary gearboxes or cardan shafts.
Spherical roller bearing
Barrel shaped rollers and curved raceways make this type self-aligning: it tolerates shaft deflection and misalignment of up to several degrees. Used mainly in paper machines, heavy machinery and wind turbines.
Angular contact roller bearing
Angular contact roller bearings combine high radial and moment loads with high stiffness. They are used particularly in slewing rings, at Franke as type LVG.
Roller bearing vs. ball bearing – which type when?
| Property | Roller bearing | Ball bearing |
|---|---|---|
| Type of contact | line contact | point contact |
| Radial load capacity | very high | medium |
| Max. rotational speed | medium | high |
| Shock load | well suited | limited |
| Misalignment tolerance | typically low (except spherical roller bearings) | low |
| Typical application | gearboxes, rotary tables, cranes | electric motors, pumps |
Typical applications of roller bearings
- Medical technology – ceiling pendant, computer tomograph, C-arm X-ray device
- Robotics & automation – articulated robot, tool changer
- Intralogistics – steering gear for automated guided vehicles (AGV)
- Special vehicles – rotating mounts on emergency and tracked vehicles
- Antenna technology – antenna bearings, satellite antennas
- Camera technology – camera crane
Roller bearings from Franke: the wire race bearing principle
Franke develops roller bearings that go far beyond the standard. With the wire race bearing principle, steel wires inserted into the customer’s design take over the function of the inner or outer ring. The rolling elements run directly on these wires – this saves weight and installation space.
The Franke angular contact roller bearings type LVG are particularly suitable for high moment loads in slewing rings: double row slewing ring made of aluminium with high moment load capacity, diameter 200 to 400 mm.
Further Franke roller bearings with crossed rollers:
- Type LEW – wire race bearing with crossed rollers for high stiffness and moment loads, diameter 150 to 400 mm
- Type LVW – ready to install slewing ring made of anodised aluminium with crossed rollers, diameter 200 to 500 mm
More about the wire race bearing principle | Bearing product overview
Frequently asked questions about roller bearings
What is a roller bearing?
A roller bearing is a rolling bearing that uses cylindrical, tapered or needle shaped rollers as rolling elements. Compared with ball bearings, the contact between roller and raceway is a line contact instead of a point contact. This allows significantly higher radial loads with a compact design.
What is the difference between a roller bearing and a ball bearing?
The main difference lies in the contact area between rolling element and raceway: ball bearings have point contact and are suitable for high speeds at moderate loads. Roller bearings have line contact, which allows higher radial loads but limits the maximum speed. Roller bearings are therefore ideal for slow running, heavily loaded bearing arrangements.
What types of roller bearings are there?
The most important roller bearing types are: cylindrical roller bearings (high radial load, low axial load), tapered roller bearings (combined radial and axial loads), needle roller bearings (very low section height with high load capacity), spherical roller bearings (self-aligning in case of misalignment) and angular contact roller bearings (high combined loads, e.g. in slewing rings). The choice depends on the load case, the speed and the available installation space.
When should I use a roller bearing instead of a ball bearing?
Roller bearings are the better choice for high radial loads, low to medium speeds, shock and vibration loads and when high static load capacity is required. Typical applications are gearboxes, rolling mills, construction cranes, heavy machine tools and rotary tables. For very high speeds or small combined loads, ball bearings are preferable.
How does the Franke wire race bearing principle work for roller bearings?
In Franke wire race bearings, the raceways are not manufactured as solid steel rings but replaced by steel wires inserted into the customer’s design. The rolling elements run directly on these wires. This saves weight and installation space, as solid outer and inner rings are omitted and the raceway is integrated directly into the housing component.
Further terms in the Franke glossary: Rolling bearing | Ball bearing | Slewing ring
Franke also manufactures bearings individually to your specifications: Individual bearing program