INA GRAE25-NPP-B 25x52x31 Radial Insert Ball Bearing

• INA GRAE25-NPP-B 25x52x31 Radial Insert Ball Bearing

  INA GRAE25-NPP-B is a radial insert ball bearing with a 25 mm bore, 52 mm spherical outside diameter and 31 mm overall width B1. Its design combines a spherical outer ring surface, seals on both sides and an eccentric locking collar for locating the bearing on the shaft. The current Schaeffler designation for this bearing is GRAE25-XL-NPP-B.

  Exact product identification:

  INA + GRAE25-NPP-B + GRAE25-XL-NPP-B + 25x52x31 mm + radial insert ball bearing + spherical outer surface + eccentric locking collar

  INA GRAE25-NPP-B – Technical Characteristics

  Parameter	Specification
  Brand	INA
  Manufacturer	Schaeffler
  Designation	GRAE25-NPP-B
  Current designation	GRAE25-XL-NPP-B
  Bearing type	Radial insert ball bearing
  Bore diameter d	25 mm
  Outside diameter Dsp	52 mm
  Overall width B1	31 mm
  Width B	21.4 mm
  Outer ring width C	15 mm
  Outer ring	Spherical outside surface
  Shaft location	Eccentric locking collar
  Bore	Cylindrical
  Sealing	Both sides
  Basic dynamic load rating Cr	14 kN
  Basic static load rating C0r	7.8 kN
  Mass	approx. 0.19 kg

  INA GRAE25-NPP-B Dimensions – 25x52x31 mm

  The commonly used dimensional description:

  25x52x31 mm

  must be interpreted correctly for this insert bearing.

  d = 25 mm – bore diameter

  Dsp = 52 mm – spherical outside diameter

  B1 = 31 mm – overall width including the extended inner-ring and locking arrangement

  Additional catalogue dimensions include:

  B = 21.4 mm

  C = 15 mm – outer ring width

  Therefore, 31 mm should not be interpreted as the width of the outer ring.

  This distinction is particularly important when comparing GRAE25 with other insert-bearing designs.

  What Is INA GRAE25-NPP-B?

  INA GRAE25-NPP-B belongs to the radial insert ball bearing family.

  These bearings are designed for installation in compatible bearing housings. The characteristic spherical outside surface of the outer ring works with a correspondingly shaped housing seat.

  This arrangement allows the installed bearing unit to compensate for limited static misalignment resulting from mounting.

  GRAE25-NPP-B should not be confused with a conventional double row self-aligning ball bearing. Its self-aligning capability results from the spherical outer ring/housing interface, not from two rows of balls operating on a spherical raceway.

  Spherical Outer Ring Surface

  A key construction feature of INA GRAE25-NPP-B is its:

  spherical outside surface.

  The spherical outer surface is designed to fit a compatible housing with a matching spherical bearing seat.

  This geometry allows the bearing and housing combination to compensate for limited alignment errors caused by installation.

  The housing design is therefore an important part of correct bearing selection.

  Eccentric Locking Collar

  INA GRAE25-NPP-B is secured to the shaft using an:

  eccentric locking collar.

  This locking method is one of the most important identification features of the GRAE series.

  The eccentric collar engages with the eccentric extension of the bearing inner ring and is rotated to lock the assembly before final securing.

  When replacing this bearing, the locking method must be considered together with bore size, outer-ring geometry and sealing arrangement.

  What Does NPP Mean?

  The NPP suffix is associated with the sealed design of this INA radial insert bearing.

  GRAE25-NPP-B is sealed on both sides.

  The sealing system helps protect the rolling elements and raceways from contamination while helping retain lubricant within the bearing.

  Seal design should therefore be checked when selecting an alternative bearing.

  What Does GRAE25-NPP-B Mean?

  The complete designation:

  GRAE25-NPP-B

  identifies a specific INA radial insert bearing design.

  For practical product identification, the key elements are:

  GRAE25 – bearing size with a 25 mm bore

  NPP – sealed bearing configuration

  B – part of the manufacturer's specific design designation.

  Suffix systems differ between bearing manufacturers. Individual letters should therefore not be interpreted using the designation system of another brand.

  GRAE25-NPP-B vs GRAE25-XL-NPP-B

  The bearing is widely known under the designation:

  GRAE25-NPP-B.

  In current Schaeffler documentation, the designation appears as:

  GRAE25-XL-NPP-B.

  This is important for search and identification because maintenance departments and buyers may encounter either reference in:

  older technical documentation

  existing machines

  bearing markings

  ERP databases

  supplier catalogues

  or:

  current Schaeffler documentation.

  For this reason, both GRAE25-NPP-B and GRAE25-XL-NPP-B are valuable identification terms for this product.

  Basic Dynamic Load Rating Cr

  The basic dynamic load rating is:

  Cr = 14,000 N = 14 kN.

  Cr is a standardized parameter used when calculating bearing rating life under dynamic loading.

  It should not be interpreted as a simple maximum permissible load under all operating conditions.

  Basic Static Load Rating C0r

  The basic static load rating is:

  C0r = 7,800 N = 7.8 kN.

  This value is used when evaluating the bearing under static loading or operating conditions involving very slow movement.

  INA GRAE25-NPP-B as an Insert Bearing

  A search for:

  INA insert bearing 25mm

  may refer to several different bearing designs.

  GRAE25-NPP-B is specifically identified by the combination of:

  25 mm cylindrical bore

  52 mm spherical outside diameter

  31 mm overall width B1

  spherical outer ring surface

  eccentric locking collar

  and:

  double-sided sealing.

  These features should be considered together when identifying the correct bearing.

  Selection and Interchangeability

  When selecting an alternative to INA GRAE25-NPP-B, do not compare only the nominal 25x52x31 mm dimensions.

  Check:

  bearing type – radial insert ball bearing

  d = 25 mm

  Dsp = 52 mm

  B1 = 31 mm

  B = 21.4 mm

  C = 15 mm

  spherical outer ring surface

  eccentric locking collar

  sealing configuration

  housing compatibility

  required load ratings

  and:

  shaft and mounting requirements.

  A bearing with a 25 mm bore and 52 mm outside diameter is not automatically interchangeable with INA GRAE25-NPP-B.

  How Is INA GRAE25-NPP-B Searched Online?

  Buyers may search for this bearing using the original designation, current Schaeffler designation, dimensions, locking method or generic insert-bearing terminology.

  Common search variants include:

• INA GRAE25-NPP-B
• GRAE25-NPP-B INA
• INA GRAE 25 NPP B
• GRAE 25 NPP B INA
• GRAE25 NPP B
• GRAE 25 NPP B
• INA GRAE25
• GRAE25 INA
• INA GRAE25-XL-NPP-B
• GRAE25-XL-NPP-B INA
• INA GRAE25 XL NPP B
• GRAE25 XL NPP B
• GRAE25 bearing
• INA GRAE25 bearing
• GRAE25 NPP B bearing
• GRAE25-NPP-B bearing
• GRAE25 XL NPP B bearing
• GRAE25 insert bearing
• INA GRAE25 insert bearing
• GRAE25 radial insert bearing
• INA GRAE25 radial insert bearing
• GRAE25 radial insert ball bearing
• INA radial insert ball bearing 25mm
• INA insert bearing 25mm
• INA insert bearing 25x52x31
• insert bearing 25x52x31
• 25x52x31 bearing
• 25x52x31 insert bearing
• INA bearing 25x52x31
• INA 25x52x31 bearing
• 25mm insert bearing
• 25mm bore insert bearing
• 25mm radial insert bearing
• 52mm OD insert bearing
• 25mm bore 52mm OD bearing
• 25mm ID 52mm OD bearing
• eccentric collar bearing 25mm
• eccentric locking collar bearing 25mm
• INA eccentric collar bearing
• INA eccentric locking collar bearing
• GRAE25 eccentric collar bearing
• spherical OD insert bearing 25mm
• spherical outer ring bearing 25mm
• sealed insert bearing 25mm
• double sealed insert bearing 25mm

Regardless of the search format, the product described on this page is:

INA GRAE25-NPP-B / GRAE25-XL-NPP-B with d = 25 mm, Dsp = 52 mm and B1 = 31 mm.

GRAE25-NPP-B 25x52x31 – Is the 31 mm Width Correct?

Yes, but the dimension must be interpreted correctly.

The common commercial size:

25x52x31 mm

corresponds to:

25 mm – bore diameter d

52 mm – outside diameter Dsp

31 mm – overall width B1.

The additional catalogue dimensions are:

B = 21.4 mm

and:

C = 15 mm.

Therefore, describing the product simply as a 25x52x31 bearing is useful for searching, but the complete dimensional drawing should be considered when checking interchangeability.

INA GRAE25 – Old and Current Designations

A bearing, machine manual or older purchasing record may identify the product as:

INA GRAE25-NPP-B.

Current Schaeffler documentation may identify the corresponding product as:

INA GRAE25-XL-NPP-B.

Including both references is especially useful for MRO, industrial maintenance and spare-parts sourcing, where the reference copied from an installed bearing may differ from the designation found in a current catalogue.

GRAE25 Bearing with Eccentric Locking Collar

The locking method is a useful search and identification feature.

Users looking for:

25mm eccentric collar bearing

INA eccentric locking bearing

or:

GRAE25 eccentric collar bearing

may be searching for this bearing family.

However, the locking collar alone does not confirm interchangeability. The complete geometry and housing compatibility must also be checked.

Technical Specification

FAQ

What are the dimensions of INA GRAE25-NPP-B?

The commonly quoted size is 25x52x31 mm: bore diameter d = 25 mm, outside diameter Dsp = 52 mm and overall width B1 = 31 mm.

Is GRAE25-NPP-B the same designation as GRAE25-XL-NPP-B?

GRAE25-NPP-B is the earlier designation commonly found in the market, while current Schaeffler documentation uses GRAE25-XL-NPP-B for this product.

Is INA GRAE25-NPP-B a self-aligning bearing?

It is a radial insert ball bearing with a spherical outer ring surface. When installed in a compatible spherical housing seat, the bearing unit can compensate for limited static misalignment. It should not be confused with a conventional double row self-aligning ball bearing.

How is INA GRAE25-NPP-B secured to the shaft?

The bearing uses an eccentric locking collar to secure the inner ring to the shaft.

Is the bearing width 31 mm?

31 mm is the overall width B1. The additional catalogue dimensions include B = 21.4 mm and outer ring width C = 15 mm.

What is the dynamic load rating of INA GRAE25-NPP-B?

The basic dynamic load rating is Cr = 14 kN.

What is the static load rating?

The basic static load rating is C0r = 7.8 kN.

Can any 25x52x31 bearing replace INA GRAE25-NPP-B?

No. Verify the complete geometry, spherical outer surface, B/B1/C dimensions, eccentric locking system, sealing arrangement, housing compatibility and required load ratings.

AI Overview

INA GRAE25-NPP-B, currently designated GRAE25-XL-NPP-B, is a radial insert ball bearing with a 25 mm bore, 52 mm spherical outside diameter and 31 mm overall width B1. It features double-sided sealing and an eccentric locking collar for shaft location. It is also searched as GRAE25 bearing, INA GRAE 25 NPP B and 25x52x31 insert bearing.

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