Description
Traceable Supply Chain — Every INA NK70/35-XL needle roller bearing we ship carries batch-level traceability from authorized distributor channels, backed by verifiable documentation packages tailored for industrial importers.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | INA NK70/35-XL |
| Bearing Type | Needle Roller Bearing |
| Bore Diameter (Fw) | 70 mm |
| Outside Diameter (D) | 85 mm |
| Width (B) | 35 mm |
| Weight | 0.383 kg |
| Cage Material | Steel Cage |
| Seal or Shield Type | Open |
| Number of Rows | Single Row |
| Load Direction | Radial |
| Style | Without Outer Ring, Without Inner Ring |
| Material | Bearing Steel |
| X-Life Designation | XL (optimized internal geometry) |
The XL suffix in the INA NK70/35-XL reflects X-Life series branding; full dimensional and dynamic load confirmation should be referenced against the current INA catalog edition.
Application Suitability
| Industry | Typical Applications |
|---|---|
| Industrial Gearboxes | Main shaft support, intermediate gear clusters |
| Material Handling | Conveyor drive reducers, bucket elevator gearmotors |
| Power Transmission | Coupling adapter assemblies, speed reducer output shafts |
What a Cage Failure Costs Inside a Heavy Gearbox
A fractured steel cage in a needle roller bearing doesn’t just stop one shaft — it sends debris through the entire gear train.
Gearbox maintenance teams know the aftermath: unplanned downtime, secondary gear tooth damage, and a teardown that lasts days instead of hours. The INA NK70/35-XL needle roller bearing is designed for these high-radial-load environments where compact cross-section and cage integrity under shock loads are non-negotiable. Yet the supply chain is full of look-alike bearings with nylon cages substituted where steel was specified, or heat treatment shortcuts that leave rollers prone to spalling within months [NEED_CITE: rolling bearing failure mode classification per ISO 15243]. I once saw a mining customer’s production line shut down after a substitute needle roller bearing with the wrong cage material shattered inside a heavy gearbox under shock load. That three-month-old failure traced back to a cross-reference that matched the base number but ignored cage type entirely.
How the INA NK70/35-XL Fits Gearbox Load Profiles
Heavy gearboxes demand bearings that handle sustained radial loads while fitting into tight radial envelopes. The INA NK70/35-XL needle roller bearing delivers exactly that: a 70 mm bore, 85 mm OD, and 35 mm width that pack substantial load-carrying capacity without requiring a larger housing bore. The open design allows direct oil splash or bath lubrication from the gearbox sump, eliminating the need for sealed-for-life arrangements that fail when grease degrades at sustained operating temperatures. We’ve cross-checked this model against OEM gear reducer drawings for material handling and mining conveyors where envelope constraints rule out standard deep groove or spherical roller alternatives.
Thermal Expansion, Lubrication Access, and Shock Loads
Gearbox environments combine moderate speeds with heavy radial loads and frequent shock events — think conveyor startups under full load or crusher feed surges transmitted through reduction stages. Operating temperatures inside a gearbox housing typically climb above ambient, demanding either C3 clearance or careful thermal analysis before specifying standard clearance. Oil-bath lubrication at these temperatures requires open bearing designs that allow continuous oil circulation, washing away wear debris before it embeds in raceways [NEED_CITE: gearbox bearing lubrication and thermal expansion clearance selection]. Installation in split housings or blind bore locations also means the bearing must tolerate press-fit assembly without cage deformation, which is where the steel cage on the NK series proves its worth over polymer alternatives.
Reading the INA NK70/35-XL Designation
The NK prefix tells you immediately this is a caged needle roller bearing without an inner ring — the shaft itself serves as the inner raceway, which demands a hardened and ground shaft surface (typically HRC 58–62). The 70/35 dimension block gives Fw and B directly, meaning the shaft diameter at the bearing seat must be 70 mm with appropriate geometric tolerances. The XL designation marks INA’s X-Life series, indicating optimized roller profiling and raceway geometry for extended fatigue life under heavy contact stress. Steel cage construction means this bearing can handle the vibration and shock spectra common in industrial power transmission without cage pocket wear accelerating unexpectedly.
The Real Cost of a Wrong Cross-Reference
Substituting a needle roller bearing based only on bore and OD is how premature failures start. A cross-reference that matches dimensions but ignores cage material, internal geometry, or clearance class sends a bearing into service that looks right on paper but fails in the field. Misapplication shows up as cage fracture, roller skidding, or raceway spalling — all classified under ISO 15243 failure modes that trace back to selection or sourcing errors rather than manufacturing defects [NEED_CITE: ISO 281 bearing life calculation and application factors]. Warranty claims get denied when the failure analysis report points to incorrect specification at procurement, leaving the maintenance budget to absorb the full replacement and downtime cost.
Why Procurement Engineers Source Through Us
We don’t hold a single-brand distributorship; we source the INA NK70/35-XL needle roller bearing through authorized INA distributor channels with full batch traceability. Every shipment includes documentation that satisfies import compliance and buyer authenticity audits — Certificate of Conformity, material certification, and country-of-origin papers. Our cross-reference database matches not just base dimensions but cage material, clearance, and precision suffixes across SKF, NSK, FAG, TIMKEN, NTN, and KOYO, so substitutions are engineering-verified rather than catalog-skimmed. For MRO teams replacing bearings by OEM equipment number, we trace back to the original specification including internal geometry variants that generic catalogs flatten into one line.
Documentation & Authenticity
- Supplier Certificate of Conformity tied to the specific batch and lot number of your INA NK70/35-XL shipment, enabling traceability from our warehouse back to the authorized distributor entry point
- Material certificate confirming bearing steel grade and heat treatment compliance for the needle rollers and steel cage assembly
- Third-party dimensional inspection report covering Fw, D, and B tolerances checked against ISO 492 before dispatch
- Country-of-origin documentation prepared for import clearance, including HS code reference for customs classification in destination markets
Storage, Handling & Mounting
- Keep the INA NK70/35-XL in its original sealed packaging until the moment of installation; the open design means any contaminant ingress during storage will embed directly into the unlubricated needle roller paths
- Shaft journal hardness must be verified at HRC 58–62 before mounting, since this bearing runs without an inner ring and a soft shaft surface will spall under the 70 mm needle contact patch
- Press-fit assembly should use a sleeve tool acting on the outer ring only; forcing through the steel cage or rollers will distort pocket geometry and cause early cage wear in gearbox vibration spectra
- Confirm gearbox oil level and circulation before first run — the open bearing relies entirely on splash or bath lubrication from the housing, and dry startup will score raceways within minutes
Start Your Technical Review
Share your gearbox application parameters — load spectrum, operating temperature range, and lubrication method — so we can confirm the INA NK70/35-XL needle roller bearing is the correct specification for your service conditions. If you’re replacing an existing bearing by OEM equipment number, send us the plate data and we’ll cross-verify the full suffix string before quoting.
Frequently Asked Questions
Q: How can I verify the authenticity of an INA needle roller bearing after delivery?
A: Genuine INA bearings carry traceable batch markings that can be cross-referenced through the Schaeffler/INA official verification channels. We supply a Certificate of Conformity with each shipment that links your specific bearing to its authorized distributor chain, and we guide buyers through the verification process before installation.
Q: What does the XL suffix mean on INA needle roller bearings?
A: XL designates INA’s X-Life series, which indicates optimized internal geometry — specifically improved roller end profiling and raceway surface finish — engineered to extend fatigue life under sustained heavy radial loads compared to standard series equivalents.
Q: What shaft preparation is needed when installing a needle roller bearing without an inner ring?
A: The shaft journal itself acts as the inner raceway, so it must be hardened to HRC 58–62, ground to the appropriate dimensional tolerance for a 70 mm seat, and finished to a surface roughness that prevents premature roller wear. Shaft deflection under load should also be checked, as needle rollers are sensitive to misalignment.
Q: What are the differences between NK, NA, and RNA series needle roller bearings?
A: NK series are caged needle roller bearings without an inner ring. NA series include an inner ring for applications where the shaft cannot be hardened or ground to raceway quality. RNA series are similar to NK but follow a different dimensional envelope standard. Selection between them depends on shaft preparation capability and available radial space.
Q: What lubrication method is recommended for open-type needle roller bearings in gearboxes?
A: Oil-bath or splash lubrication from the gearbox sump is standard for open-type needle roller bearings like the NK70/35-XL. The oil must reach the bearing at sufficient volume to carry heat away from the needle contact zones and flush wear debris. Grease lubrication is generally unsuitable in these enclosed, continuously operating environments due to thermal degradation and inability to purge contaminants.
Confirm Your Specification and Request Documentation
Send us your application parameters or OEM part number, and we’ll return a verified cross-reference with full documentation package for your approval.
