JFK IR inner rings

JFK Needle Roller Bearings

  • Complementary components for bearings without rings
  • Optimized sliding surface
  • Oversized widths available

IR inner rings are separate components designed for use with needle roller bearings without an inner ring: NK needle roller bearings, HK/BK drawn cup needle roller bearings and K/KBK/KZK needle roller cages. Mounted on the shaft, they provide the raceway surface for the needle rollers and eliminate the need to harden and grind the shaft itself, simplifying the design and reducing machining costs. IR series inner rings for needle roller bearings are manufactured from hardened and ground steel with the required hardness and surface roughness.

JFK Group offers IR inner rings in different widths, including versions with increased width compared to the matching bearing, suitable for applications with high axial displacement between shaft and housing. Available with lubrication holes to enable relubrication through the shaft.

Versions

How to select the right IR inner ring

The selection mainly depends on whether axial displacement between shaft and housing is present in the application. The standard width covers direct matches with the bearing, while the increased width is required when the bearing must be able to move axially on the inner ring.

  1. IR inner ring with standard width

    Width matching the paired bearing (NK, HK/BK or K/KBK/KZK). The reference solution for applications where no axial displacement between shaft and housing is expected, with the raceway surface aligned with the bearing. Width equal to the bearing · Direct mounting · No axial displacement

  2. IR inner ring with increased width

    Increased width compared to the paired bearing, for applications with high axial displacement between shaft and housing. It allows the bearing to move axially on the inner ring while maintaining contact with the raceway surface, without requiring additional guides. High axial displacement · Bearing sliding on the inner ring · No additional guides

Performances

Design and performance features

Optimized raceway surface for needle rollers, allowing axial displacement and installation on untreated shafts.

Benefit

Function

Inner raceway for bearings without inner rings Provides an optimized raceway surface for the needle rollers of NK, HK/BK and K/KBK/KZK bearings, eliminating the need to harden and grind the shaft. Allows the installation of bearings without inner rings on untreated shafts.

Benefit

Width

Standard and increased available Available in standard width, matching the paired bearing, and in increased width for applications with high axial displacement between shaft and housing. The increased width allows the bearing to move axially on the inner ring.

Benefit

Lubrication

Lubrication holes available Available with lubrication holes to ensure relubrication through the shaft in applications where external lubrication is not feasible.

Benefit

Material

Hardened and ground steel Manufactured from hardened and ground steel to provide the required hardness and surface finish for reliable needle roller performance.

Benefit

Compatibility

Con NK, HK/BK, K/KBK/KZK bearings Designed to be paired with JFK needle roller bearings without an inner ring: NK needle roller bearings, HK/BK drawn cup needle roller bearings and K/KBK/KZK needle roller cages.

Mounting

IR inner ring mounting

The IR inner ring is mounted on the shaft with an interference fit before positioning the bearing. The bearing is then mounted onto the inner ring. For increased-width versions, verify that the expected axial displacement is within the available width of the inner ring.

Installation Mounting

  1. Press fitting onto the shaftThe inner ring is mounted on the shaft by press fitting. Check the fitting tolerances before installation.
  2. Bearing installation on the inner ringAfter mounting the inner ring on the shaft, the needle roller bearing is positioned on the inner ring. The outer surface of the ring acts as the raceway for the needle rollers.

Technical data

Function
Inner raceway for bearings without inner rings
Width
Standard and increased available
Lubrication
Lubrication holes available
Material
Hardened and ground steel
Compatibility
Con NK, HK/BK, K/KBK/KZK bearings

Applications

Applications

Components and application support for every industrial environment.

Discover
JFK Needle Roller Bearings

Industrial automation

Applications with NK needle roller bearings or drawn cup needle roller bearings on shafts that cannot be heat treated. The IR inner ring eliminates the need for special shaft machining, simplifying the design and reducing costs.
Discover
JFK Needle Roller Bearings

Transmissions and axles

Transmission systems with axial displacement between shaft and housing. Increased-width versions allow axial movement of the bearing on the inner ring without requiring additional guides.
Discover
JFK Needle Roller Bearings

Metal Fabrication / Machining Industry

Machine tools with shafts that cannot be hardened for design or cost reasons. The IR inner ring allows the use of needle roller bearings without modifying the shaft design.
Discover
JFK Needle Roller Bearings

Construction Equipment

Actuators and motion systems where design simplicity and reduced machining costs are critical parameters in component selection.

Contacts

Request information about this product

Complete the form for technical information, quotations or trial samples.

    Read the privacy notice (opens in a new tab)

    * Required fields

    Related products

    Please also consider these alternatives: NKI needle roller bearings already include a drawn inner ring and represent the integrated alternative solution to the NK + IR combination. HK/BK drawn cup needle roller bearings are paired with IR inner rings when the shaft cannot be heat treated. Needle roller cages are paired with IR inner rings when the housing can act as the outer raceway but the shaft cannot be treated.