Description
Genuine Sourcing Verification — Every INA NK28/20-XL leaving our warehouse ships with traceable batch documentation and QR code verification through the manufacturer’s official application, ensuring the needle rollers meet axial-tight specifications before they ever reach your assembly bench.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | INA NK28/20-XL |
| Bearing Type | Needle Roller Bearing |
| Bore Diameter (Fw) | 28mm |
| Outside Diameter (D) | 37mm |
| Width (B) | 20mm |
| Weight | 0.052kg |
| Cage Material | With Cage |
| Seal or Shield Type | Open |
| Number of Rows | Single |
| Style | Without Inner Ring, Without Outer Ring |
| Material | Bearing Steel |
| Load Direction | Radial |
| Bore Type | Shaft Riding |
The XL suffix remains unverified against the current INA catalog — confirm exact meaning with manufacturer documentation before finalizing procurement.
Application Suitability
| Industry | Typical Applications |
|---|---|
| Automotive Repair | Small gearbox needle assemblies in compact transmissions |
| Industrial Machinery | Miniature gear reducer output stages |
| Precision Mechanical Equipment | Compact transmission shaft supports |
| General MRO | Replacement needle sets in OEM compact gear units |
Why Needle Roller Axial Play Tolerances Cause Locked Gearboxes
A 28mm bore needle bearing that fits the shaft perfectly can still destroy your gear assembly in weeks if the axial-tight specification is wrong.
I once fielded a warranty call from a buyer who matched a thin-section needle roller purely on bore and outside diameter. Six weeks later, the mini gear unit locked up hot — needles gouged the inner ring, the entire batch was scrapped. With needle rollers like the INA NK28/20-XL, the suffix and tolerance stack is where everything lives or dies. Counterfeit rollers with soft cages and cloned markings pass visual inspection but fail under sustained radial load, causing premature cage fragmentation [NEED_CITE: rolling bearing failure mode classification per ISO 15243]. Cross-reference errors compound the problem when buyers substitute a standard needle set without verifying the crowned roller profile or axial play requirements specific to their housing tolerance.
Matching Compact Gear Geometry to Shaft and Housing Reality
The INA NK28/20-XL needle roller bearing runs directly on the shaft and in the housing bore — no inner ring, no outer ring. This design collapses the radial envelope to just 4.5mm of cross-section between bore and OD, which matters when your mini gearbox housing leaves almost no room for conventional bearing walls. We cross-check every replacement request against the OEM gear unit drawing to confirm the shaft hardness reaches the minimum required for direct needle contact, because installing a cage-and-roller assembly on an underspecified shaft surface leads to rapid raceway scoring.
What Compact Gearboxes Actually Demand From Their Needle Sets
Radial loads in miniature gear systems cycle through every mesh engagement, producing repeated impact pulses rather than smooth rotation. The single-row caged configuration spaces needles consistently, preventing roller skewing that uncaged full-complement sets suffer under these conditions. Temperature rise stays modest in compact enclosures, but lubrication access is often restricted — the open design here means you specify your own grease fill and replenishment interval rather than relying on a factory seal [NEED_CITE: needle roller bearing lubrication interval recommendations for enclosed gearboxes]. Assembly requires care: cold pressing the cage assembly into a tight housing bore can distort the cage if the chamfer is insufficient.
Reading the Specs That Matter for Thin-Section Needle Bearings
The 28mm bore diameter rides directly on a hardened shaft journal, eliminating the inner ring weight and radial space penalty. Bearing steel construction with a single cage row delivers consistent roller spacing, which reduces friction heat buildup in high-speed mini gear applications where even minor temperature excursions affect gear mesh accuracy. The open seal type means contamination defense falls entirely on your housing seals — a deliberate tradeoff that prioritizes low friction and flexible relubrication over sealed-for-life convenience. At 37mm outside diameter and 20mm width, this needle set handles substantial radial load relative to its footprint, but axial load capacity remains essentially zero by design.
The Downtime Bill From a Wrong Needle Roller Swap
Correct selection paired with verified sourcing prevents the cascade failure pattern: cage fragmentation scatters needles through the gear mesh, destroying mating teeth and shaft journals before the unit even triggers a vibration alarm. Wrong axial clearance specification causes thermal binding as the housing expands, locking the assembly solid. Counterfeit needle sets with substandard steel spall within the first operating cycle, sending debris through the entire gearbox [NEED_CITE: ISO 281 bearing life calculation framework and premature failure factors]. Every unplanned teardown costs more in labor and secondary damage than sourcing verified INA NK28/20-XL bearings through traceable channels in the first place.
What We Check Before Your Needle Bearings Ship
We source INA products through authorized distributor channels, which means every NK28/20-XL shipment carries batch-level documentation you can verify independently. Our cross-reference database matches bore, OD, width, cage type, and axial play suffix together — not just the base number. When a maintenance engineer calls with an OEM equipment number from a compact gear reducer, we pull the original specification and confirm whether this open-type single-row needle set actually fits the application or whether a sealed variant belongs there instead. Material certificates and dimensional inspection reports travel with the goods, and our team fields post-delivery questions about installation fit and lubrication protocol.
Documentation & Authenticity
- Supplier Certificate of Conformity with batch and lot traceability tied to your specific NK28/20-XL shipment
- QR code verification pathway through INA official application to confirm genuine manufacturer origin
- Material certificate confirming bearing steel grade for direct-shaft contact applications
- Dimensional inspection report covering Fw, D, and B tolerances before dispatch
- Country-of-origin documentation supporting import clearance and customs filing
Storage, Handling & Mounting
- Keep the INA NK28/20-XL in original sealed packaging until the moment of assembly — early exposure risks contaminating the open cage with shop dust that accelerates needle wear
- Verify shaft journal hardness and surface finish before pressing the needle set into service, since this design rides without an inner ring
- Handle with clean lint-free gloves to prevent fingerprint moisture from initiating corrosion on the bearing steel rollers before first lubrication
- Apply specified grease fill immediately after mounting, as the open type provides no factory seal to protect against dry startup
- Confirm housing bore chamfer adequacy before cold-press installation to prevent cage distortion on the 37mm OD
Request a Specification Review Before You Commit
Share your compact gearbox operating parameters — shaft speed, radial load spectrum, housing tolerance, and lubrication access — so we can confirm the INA NK28/20-XL matches your application requirements. If you are replacing an existing needle set, send the OEM equipment number and we will cross-reference the original specification including cage type and axial play details. We will return a documentation package with batch availability, lead time, and origin confirmation for your procurement records.
Frequently Asked Questions
Q: How can I verify that my INA NK28/20-XL bearings are genuine before installation?
A: Use the INA official mobile application to scan the QR code on the product packaging, which links to the manufacturer’s verification database confirming batch authenticity. Additionally, request the supplier Certificate of Conformity and cross-reference the batch number against your shipment documentation before breaking the factory seal.
Q: When should I choose a needle roller bearing without inner ring versus one with an inner ring?
A: The without-inner-ring design like the NK28/20-XL suits applications where the shaft journal is hardened and ground to bearing quality, saving radial space and weight. Choose a variant with inner ring when the shaft surface cannot meet the required hardness or finish, or when you need the flexibility to replace the bearing without remachining the shaft.
Q: What cross-reference factors matter beyond the base bore and OD numbers?
A: Cage material and configuration, axial play tolerance, roller profile crowning, and precision class all affect field performance. A needle set that matches on 28mm bore and 37mm OD but differs in cage type or axial clearance can cause thermal binding or premature cage failure in compact gear applications.
Q: How should I lubricate an open-type needle roller bearing in an enclosed gearbox?
A: Select a grease compatible with your operating temperature range and replenishment schedule, applying the manufacturer-recommended fill quantity after mounting. The open design allows visual inspection and flexible relubrication, but places contamination defense responsibility on your housing seals rather than integrated bearing seals.
Q: Does the XL suffix on the INA NK28/20-XL change the mounting procedure?
A: The XL suffix designation requires confirmation against the current INA catalog to determine its exact specification meaning. We recommend verifying the suffix interpretation with manufacturer documentation before finalizing your installation procedure and tolerance stack calculations.
Source Your Compact Gear Needle Bearings With Full Traceability
Send us your application parameters or OEM equipment number, and we will return a cross-referenced specification review with documentation availability and lead time for the INA NK28/20-XL needle roller bearing.
