INA RNA4904 25x37x17 - Needle Roller Bearing Without Inner Ring

INA RNA4904 25x37x17 mm - Needle Roller Bearing Without Inner Ring

INA RNA4904 is a single row radial needle roller bearing without an inner ring, measuring 25x37x17 mm, manufactured by INA, a brand of the Schaeffler Group. It belongs to the RNA 49 dimensional series and features a machined outer ring with a needle roller and cage assembly. The modern catalogue execution, RNA4904-XL, belongs to the Schaeffler X-life performance range. This bearing is designed to accommodate high radial loads in compact bearing arrangements where installation space is limited.

Technical Specifications - INA RNA4904-XL

Important: The 25 mm dimension refers to the diameter under the needle rollers, designated Fw. It is not the bore diameter of an inner ring because INA RNA4904 does not have an inner ring.

The load ratings and operating speeds listed above refer to INA RNA4904-XL. For older bearings marked only RNA4904, the exact execution should be verified before applying current X-life catalogue specifications.

What Does INA RNA4904 Mean?

RNA - Needle Roller Bearing Without Inner Ring

The designation RNA identifies a needle roller bearing in which the rolling elements operate directly on a suitably prepared shaft surface.

The absence of a separate inner ring reduces the radial cross-section of the bearing arrangement.

The shaft acts as the inner raceway and must therefore meet the required specifications for surface hardness, dimensional accuracy and surface finish.

49 - Bearing Dimensional Series

The 49 series includes needle roller bearings with machined outer rings and a relatively small radial cross-section.

This construction combines high radial load capacity with compact installation dimensions.

04 - Bearing Size Identification

The code 04 forms part of the bearing size designation.

For RNA4904, the diameter under the needle rollers is 25 mm.

This code should not be interpreted in the same way as the bore designation of a standard deep groove ball bearing.

XL - Schaeffler X-life Performance

The suffix XL identifies the X-life execution in Schaeffler's bearing designation system.

X-life technology incorporates improvements in bearing design, surface quality and operating performance.

For INA RNA4904-XL, the basic dynamic radial load rating is 23.7 kN, while the basic static radial load rating is 25.5 kN.

Alternative Designations and Search References

Common written variations include:

• INA RNA4904

• INA RNA 4904

• RNA4904 INA

• RNA 4904 INA

• INA RNA4904-XL

• RNA4904-XL Schaeffler

• INA needle roller bearing 25x37x17

• Needle roller bearing without inner ring 25x37x17

The designation RNA4904-XL identifies the X-life execution. The XL suffix should be retained when comparing detailed manufacturer specifications.

Construction of INA RNA4904

INA RNA4904 features a machined solid outer ring with an integral raceway and a set of needle rollers retained by a cage.

Needle rollers have a relatively small diameter compared with their length.

This geometry provides an extended contact area between the rolling elements and raceways, allowing high radial load capacity within a compact bearing cross-section.

Why Does RNA4904 Have No Inner Ring?

In the RNA design, the shaft surface replaces the raceway of a separate inner ring.

This arrangement reduces the radial dimensions of the complete bearing assembly.

However, it requires a properly prepared shaft raceway.

Shaft Raceway Requirements

A shaft operating directly against needle rollers must provide suitable:

• Surface hardness.

• Raceway surface finish.

• Roundness and cylindricity.

• Dimensional accuracy.

• Resistance to rolling contact fatigue and wear.

An ordinary unhardened shaft surface may not meet the requirements for direct needle roller contact.

If a suitable shaft raceway cannot be provided, an appropriate separate inner ring or a bearing design incorporating an inner ring should be considered.

INA RNA4904-XL Load Ratings

Basic Dynamic Radial Load Rating Cr - 23.7 kN

The basic dynamic radial load rating is used to calculate rolling bearing fatigue life under dynamic loading conditions.

It does not represent an unconditional maximum permissible operating load.

Actual bearing life depends on the equivalent radial load, lubrication, operating temperature, contamination and raceway condition.

Basic Static Radial Load Rating C0r - 25.5 kN

The basic static radial load rating is used to assess the risk of permanent deformation at the rolling element and raceway contacts.

It is particularly relevant under static loads, slow rotation and shock loading.

Axial Load Capacity

INA RNA4904 is primarily designed to accommodate radial loads.

It should not be used as the sole means of locating a shaft axially in both directions.

Axial forces must be accommodated by suitable locating elements or a separate bearing arrangement designed for axial loading.

Operating Speeds - INA RNA4904-XL

The following speed values are specified for RNA4904-XL:

The reference speed is a thermal reference value determined under specified operating conditions.

The limiting speed reflects restrictions associated with bearing construction and operating characteristics.

Actual permissible operating speed depends on load, lubrication method, temperature and the accuracy of the shaft raceway.

Oil Lubrication vs Grease Lubrication

Needle roller bearings can operate with oil or grease lubrication, depending on the bearing arrangement and operating requirements.

Oil lubrication may be appropriate in gearbox assemblies and systems with an established oil circulation or oil bath arrangement.

Grease lubrication may be suitable for other applications, provided that lubricant supply and operating speed requirements are satisfied.

The lubrication method must be selected according to the complete mechanical system.

INA RNA4904 vs INA NA4904

When Should INA RNA4904 Be Selected?

RNA4904 is suitable for consideration when the shaft can serve directly as the inner raceway.

This design reduces the radial installation space required by the bearing arrangement.

When Should INA NA4904 Be Selected?

NA4904 includes its own inner ring.

It may be more suitable where the shaft cannot be prepared to act directly as a needle roller raceway.

The two bearings are not directly interchangeable without checking shaft diameter and the complete assembly design.

INA RNA4904 vs Other Executions

Sealed executions may have different load ratings and permissible operating speeds compared with the open version.

Technical values should not be transferred between different executions without verifying the manufacturer's specifications.

Bearing Selection and Interchangeability

Before ordering INA RNA4904, verify:

• Complete designation RNA4904 or RNA4904-XL.

• Diameter under rollers Fw of 25 mm.

• Outside diameter D of 37 mm.

• Bearing width C of 17 mm.

• Absence of an inner ring.

• Shaft raceway hardness and surface finish.

• Required radial load capacity.

• Rotational speed.

• Lubrication method and lubricant supply.

• Operating temperature.

• Outer ring fit in the housing.

• Axial location requirements.

• Compatibility with the complete bearing arrangement.

Dimensional Alternatives

Bearings with the basic designation RNA4904 are also available from other manufacturers, including SKF RNA 4904 and NTN RNA4904R.

Matching dimensions of 25x37x17 mm do not automatically establish complete interchangeability.

Load ratings, tolerances, cage construction, lubrication requirements and operating conditions must also be considered.

Applications of INA RNA4904

INA RNA4904 can be considered for compact mechanical assemblies requiring high radial load capacity within limited installation space.

Potential application categories include:

• Industrial gearboxes.

• Rotating shaft assemblies.

• Production machinery.

• Material-handling equipment.

• Mechanical drive systems.

• Compact bearing arrangements without separate inner rings.

Selection for a particular machine requires verification of operating loads, speed, lubrication and shaft raceway characteristics.

Specific OEM applications should not be attributed to INA RNA4904 without supporting technical documentation.

Installation and Operating Recommendations

Shaft Raceway Preparation

Before installation, inspect the shaft raceway.

The surface must be suitably hardened, ground and manufactured to the required dimensional accuracy.

Surface defects, inadequate hardness or excessive roughness can reduce bearing life.

Outer Ring Installation

When pressing the bearing into a housing, apply mounting force to the outer ring.

Do not transmit mounting force through the needle rollers.

Lubrication

The open RNA4904 execution requires an appropriate lubricant supply during operation.

Oil or grease lubrication may be used depending on the bearing arrangement and operating conditions.

Protection Against Contamination

The open execution does not have integrated seals.

Where the bearing operates in dusty or humid environments, appropriate external sealing should be provided.

Storage

Store the bearing in its original packaging in a clean, dry environment.

Protect the raceways and rolling elements from corrosion, contamination and mechanical damage.

Frequently Asked Questions - INA RNA4904

What are the dimensions of INA RNA4904?

The bearing has a diameter under rollers Fw of 25 mm, an outside diameter of 37 mm and a width of 17 mm. Its dimensions are 25x37x17 mm.

Does INA RNA4904 have an inner ring?

No. INA RNA4904 is supplied without an inner ring. The needle rollers operate directly on a suitably prepared shaft raceway.

What does Fw 25 mm mean?

Fw identifies the diameter under the needle roller set. For INA RNA4904, this dimension is 25 mm.

What is the load rating of INA RNA4904-XL?

The basic dynamic radial load rating Cr is 23.7 kN, and the basic static radial load rating C0r is 25.5 kN.

What is the limiting speed of INA RNA4904-XL?

The limiting speed is 16,900 rpm. For grease lubrication, a limiting speed of 10,100 rpm is specified.

Does INA RNA4904 require lubrication?

Yes. The open execution requires an appropriate lubricant supply during operation.

Are INA RNA4904 and INA NA4904 identical?

No. RNA4904 does not have an inner ring, while NA4904 includes one. Their shaft requirements and mounting arrangements are different.

Can SKF RNA4904 replace INA RNA4904?

SKF RNA4904 may be considered as a dimensional alternative after verifying construction, tolerances, load ratings and operating requirements. Matching dimensions alone do not guarantee full interchangeability.

INA RNA4904 - Key Technical Information

INA RNA4904 is a single row needle roller bearing without an inner ring, measuring 25x37x17 mm. Its needle rollers operate directly on a suitably prepared shaft raceway. The RNA4904-XL execution has a basic dynamic radial load rating of 23.7 kN, static radial load rating of 25.5 kN and limiting speed of 16,900 rpm.

INA RNA4904 at simmering.pl

INA RNA4904 is offered through simmering.pl, a specialist supplier of rolling bearings, sealing products and industrial mechanical components.

We support maintenance departments, machinery manufacturers, technical service companies and industrial B2B procurement customers.

Our warehouse and order processing operations are located in Lublin, Poland. We supply customers throughout the European Union and offer worldwide shipping.