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.
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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.
IR inner ring with standard width
Width equal to the bearing · Direct mounting · No axial displacementWidth 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.
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.
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.
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.
Lubrication holes available
Available with lubrication holes to ensure relubrication through the shaft in applications where external lubrication is not feasible.
Hardened and ground steel
Manufactured from hardened and ground steel to provide the required hardness and surface finish for reliable needle roller performance.
With 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.
Mounting methods
- Press fitting onto the shaftThe inner ring is mounted on the shaft by press fitting. Check the fitting tolerances before installation.
- 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
- Available widths
- Standard and increased
- Shaft fit
- Interference fit
Applications
Applications
Components and application support for every industrial environment.
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.
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.
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.
Construction Equipment
Actuators and motion systems where design simplicity and reduced machining costs are critical parameters in component selection.
Agriculture
Reliable components for heavy loads, dirt, moisture and reduced maintenance in agricultural machinery.
Automotive / Motorcycles, Trucks & Buses
Components for suspension, transmission and linkage systems designed for intensive duty cycles, vibration and compact spaces.Technical documents
Contacts
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