RNA 4904 JNS 25x37x17 mm

RNA 4904 JNS 25x37x17 mm - Needle Roller Bearing Without Inner Ring

RNA 4904 JNS 25x37x17 mm is a radial needle roller bearing manufactured by the Japanese company JNS (Nose Seiko), belonging to the RNA 49 dimensional series. The bearing features a machined outer ring and needle rollers but does not include an inner ring. Its rolling elements operate directly on a suitably prepared shaft raceway. The nominal dimensions are 25 mm roller set bore diameter (Fw), 37 mm outside diameter (D), and 17 mm bearing width (C). It is designed primarily to accommodate radial loads in compact mechanical assemblies.

Technical Specifications - RNA 4904 JNS

Important: The 25 mm dimension refers to the roller set bore diameter (Fw), not the bore diameter of an inner ring. RNA 4904 JNS is supplied without an inner ring.

JNS Catalog Parameters

The following specifications correspond to the previously referenced Nose Seiko catalog data for the standard RNA 4904 bearing.

The catalog limiting speed of 16,000 rpm applies to oil lubrication. For grease lubrication, the manufacturer recommends reducing this value to approximately 60%, equivalent to 9,600 rpm.

These are catalog reference values, not guaranteed operating limits for every installation. Current manufacturer documentation should be checked before using the values in engineering calculations.

What Does RNA 4904 JNS Mean?

The designation identifies the bearing construction, dimensional series, size code, and manufacturer.

• RNA - Needle roller bearing with an outer ring and without an inner ring.

• 49 - Dimensional series within the needle roller bearing range.

• 04 - Bearing size code within the RNA 49 series.

• JNS - Japanese bearing brand manufactured by Nose Seiko Co., Ltd.

The basic designation RNA 4904 does not contain an additional suffix identifying integrated seals, special internal clearance, precision class, or a particular cage design.

The absence of these suffixes does not establish every internal specification. Manufacturer documentation should be consulted whenever such details are essential.

RNA 4904 JNS vs RNA4904M JNS

The standard RNA 4904 designation should not be confused with RNA4904M.

JNS uses the RNA4904M designation for a stainless steel variant. These versions should not be treated as identical without checking their material specifications and operating characteristics.

Construction and Operating Principle

RNA 4904 JNS is a radial needle roller bearing consisting of an outer ring and a needle roller assembly.

Unlike bearings equipped with an inner ring, RNA 4904 allows the needle rollers to run directly against the shaft surface.

The shaft therefore acts as the inner raceway of the bearing arrangement.

This design reduces the radial installation space required for the bearing and is particularly relevant where compact shaft support is necessary.

Its principal construction characteristics include:

• No separate inner ring.

• Machined outer ring with a raceway for needle rollers.

• Compact radial cross-section.

• Rolling elements designed primarily to support radial loads.

• Compatibility with a separate inner ring when required.

• Open construction requiring suitable lubrication and contamination protection.

Shaft Raceway Requirements

Because the shaft functions as part of the rolling contact system, its surface must meet appropriate requirements for:

• Raceway hardness and wear resistance.

• Surface roughness.

• Dimensional accuracy.

• Roundness and cylindricity.

• Correct operating clearance.

• Lubrication conditions.

An improperly prepared shaft raceway may cause accelerated wear, damage to the rolling elements, and reduced bearing service life.

If the shaft cannot provide a suitable raceway, a compatible inner ring should be considered.

RNA 4904 JNS is designed primarily for radial loads and should not be used as the sole means of axial shaft location.

RNA 4904 JNS vs NA 4904 JNS

RNA 4904 and NA 4904 are related needle roller bearing configurations. Their principal difference is the presence of an inner ring.

The JNS catalog identifies IR 202517 as the corresponding inner ring for RNA 4904.

When the appropriate inner ring is used, the resulting bearing arrangement corresponds to the construction of NA 4904.

Before changing between these configurations, verify the shaft diameter, installation dimensions, fits, and axial location.

RNA 4904 and NA 4904 are not automatically interchangeable in an existing bearing arrangement.

Alternative Designations and Reference Numbers

RNA 4904 JNS may be identified using the following designation formats:

• RNA 4904 JNS

• JNS RNA 4904

• RNA4904 JNS

• JNS RNA4904

The basic designation RNA4904 also appears in the catalogs of other bearing manufacturers.

Examples of related catalog designations include:

• SKF RNA 4904

• INA RNA4904-XL

• NTN RNA4904R

These are potential alternatives requiring technical verification, not confirmed direct replacements.

Bearings from different manufacturers may differ in internal construction, tolerances, load ratings, materials, or other operating characteristics.

RNA 4904 JNS vs RNA 5904 JNS

RNA 4904 and RNA 5904 are needle roller bearings without inner rings, but they belong to different dimensional series.

The comparison uses the previously referenced JNS catalog values.

RNA 5904 has a greater width and higher catalog load ratings.

However, it cannot be considered a direct replacement for RNA 4904 without checking the available axial installation space and the complete bearing arrangement.

Bearing Selection and Interchangeability

Before purchasing RNA 4904 JNS, verify the complete designation and the technical requirements of the application.

The most important selection criteria include:

• Roller set bore diameter Fw 25 mm.

• Outside diameter D 37 mm.

• Bearing width C 17 mm.

• Shaft raceway hardness and surface finish.

• Raceway dimensional and geometrical accuracy.

• Outer ring fit in the housing.

• Required operating clearance.

• Radial load magnitude and distribution.

• Rotational speed.

• Operating temperature.

• Lubrication method.

• Protection against contamination.

• Axial location of the shaft and bearing assembly.

When selecting a replacement bearing, dimensional compatibility must be considered together with internal construction, load ratings, tolerances, and mounting requirements.

Identical nominal dimensions do not necessarily guarantee complete interchangeability between bearings from different manufacturers.

Typical Applications of RNA 4904 Needle Roller Bearings

Needle roller bearings without inner rings are used in mechanical assemblies where the shaft can function as a rolling element raceway.

Typical application categories for this bearing design include:

• Compact industrial shaft supports.

• Rotating mechanisms in industrial machinery.

• Bearing arrangements with limited radial installation space.

• Mechanical systems subjected primarily to radial loads.

• Assemblies designed for direct contact between needle rollers and the shaft raceway.

These are general applications associated with this bearing type, not verified OEM applications for the specific RNA 4904 JNS product.

Suitability for a particular machine must be established by evaluating loads, speeds, shaft construction, lubrication, and operating conditions.

Installation and Maintenance

Shaft and Housing Preparation

Before installation, inspect the shaft raceway and housing bore for cleanliness, dimensional accuracy, and surface damage.

The shaft raceway must be suitable for direct contact with needle rollers.

Correct Bearing Installation

When press-fitting the bearing into the housing, apply mounting force to the outer ring.

Do not transmit installation forces through the needle rollers, as this may damage the rolling elements or raceways.

Lubrication

RNA 4904 JNS has an open construction and requires appropriate lubrication during operation.

Lubricant selection should account for load, rotational speed, temperature, and environmental conditions.

The catalog limiting speed is 16,000 rpm with oil lubrication. For grease lubrication, the manufacturer recommends a lower limiting speed.

Actual permissible operating speed must be determined from the conditions of the complete bearing arrangement.

Storage

Store the bearing in a clean, dry environment protected from moisture, dust, and other contaminants.

Keep it in its protective packaging until installation whenever possible.

Frequently Asked Questions - RNA 4904 JNS

1. What are the dimensions of RNA 4904 JNS?

RNA 4904 JNS has a roller set bore diameter of 25 mm, an outside diameter of 37 mm, and a width of 17 mm. Its dimensional specification is 25x37x17 mm.

2. Does RNA 4904 JNS have an inner ring?

No. The bearing is designed without an inner ring. Its needle rollers operate directly on a suitably prepared shaft raceway.

3. What is the dynamic load rating of RNA 4904 JNS?

The previously referenced JNS catalog specifies a basic dynamic load rating Cr of 21,000 N.

4. What is the static load rating of RNA 4904 JNS?

The basic static load rating C0r is 25,000 N according to the referenced JNS catalog data.

5. What is the limiting speed of RNA 4904 JNS?

The catalog limiting speed is 16,000 rpm with oil lubrication. The actual permissible operating speed depends on the bearing arrangement and operating conditions.

6. Which inner ring is compatible with RNA 4904 JNS?

The corresponding inner ring identified by JNS is IR 202517. Correct fits and installation dimensions must be verified before assembly.

7. Are RNA 4904 and NA 4904 identical bearings?

No. RNA 4904 is supplied without an inner ring, whereas NA 4904 includes one. Their shaft diameter requirements and mounting configurations differ.

8. Can RNA 4904 JNS be replaced with an SKF or INA bearing?

An appropriate SKF RNA 4904 or INA RNA4904-XL bearing may be considered after confirming dimensional compatibility, tolerances, construction, load ratings, and operating requirements.

RNA 4904 JNS - Key Product Information

RNA 4904 JNS is a radial needle roller bearing manufactured by the Japanese company Nose Seiko, belonging to the RNA 49 series. It has dimensions of 25x37x17 mm and does not include an inner ring. The needle rollers operate directly on a suitably prepared shaft raceway. The bearing primarily accommodates radial loads. Its corresponding inner ring is IR 202517.

RNA 4904 JNS is offered by simmering.pl, a specialist supplier of industrial bearings and mechanical components with a warehouse in Lublin, Poland. The company serves industrial customers, maintenance departments, and technical purchasing teams, providing stock in Poland and international shipping.