RNA 6904 INA 25x37x30 Needle Roller Bearing

RNA 6904 INA 25x37x30 Needle Roller Bearing

The RNA 6904 INA 25x37x30 is a compact needle roller bearing without an inner ring designed for mechanical systems where the shaft itself serves as the inner raceway.

This bearing belongs to the INA needle roller bearing family produced by the Schaeffler Group, widely used in gearboxes, industrial transmissions and mechanical assemblies where high radial load capacity and minimal installation space are required.

By using long and thin needle rollers instead of balls, the RNA 6904 INA 25x37x30 needle roller bearing can support very high radial loads while maintaining a compact cross section, making it ideal for compact transmission systems and precision mechanical assemblies.

Bearing design and construction

Needle roller bearings use cylindrical rollers with a very small diameter relative to their length. This design increases the contact surface between rolling elements and raceways.

The RNA 6904 INA bearing includes:

outer ring made from high quality bearing steel
precision needle rollers
roller cage guiding the rolling elements
design without inner ring
shaft acting directly as the inner raceway

Because there is no inner ring, the bearing requires a hardened and ground shaft surface to ensure proper operation and durability.

Technical parameters

Model: RNA 6904
Manufacturer: INA Schaeffler
Bearing type: needle roller bearing without inner ring
Inner diameter F: 25 mm
Outer diameter D: 37 mm
Width B: 30 mm
Design: single row needle roller bearing
Rolling elements: steel needle rollers

The 25x37x30 needle roller bearing size is commonly used in compact mechanical systems where high load capacity must be combined with a small radial installation space.

Industrial applications

INA needle roller bearings are widely used in applications where high radial loads occur and compact bearing arrangements are required.

Typical applications include:

industrial gearboxes
machine tool mechanisms
production machinery
automotive transmissions
material handling equipment
hydraulic systems
compact mechanical drive systems

In many applications the shaft is hardened and ground to function directly as the inner raceway of the bearing.

Operational advantages

The INA RNA 6904 needle roller bearing offers several advantages in demanding mechanical systems.

very high radial load capacity
compact bearing design
efficient use of installation space
high precision shaft guidance
reduced overall weight of the mechanism
long service life under heavy loads

These characteristics make needle roller bearings essential components in modern mechanical engineering.

Role within the INA needle roller bearing category

The RNA 6900 series belongs to the family of needle roller bearings without inner rings. These bearings are designed for applications where the shaft can act directly as the raceway, allowing more compact bearing arrangements.

Within the category of INA needle roller bearings, the RNA 6904 size is frequently used in gearboxes and mechanical systems requiring high load capacity with minimal radial space.

FAQ

What does RNA mean in a needle roller bearing

RNA indicates a needle roller bearing without an inner ring where the shaft acts as the inner raceway.

Why do needle roller bearings not always have an inner ring

Removing the inner ring allows a more compact design and increases the load capacity when the shaft surface can function as a raceway.

What loads can needle roller bearings support

Needle roller bearings are primarily designed to support high radial loads.

Where is the RNA 6904 bearing commonly used

It is commonly used in gearboxes, industrial machinery, automotive mechanisms and compact transmission systems.