1 Model Information & Technical Parameters

Model：NN 3014 TN/SP

Dimensions

Bore d：70 mm

Outer diameter D：110 mm

Width B：30 mm

Bore type: Straight cylindrical bore

Radial clearance: C1 minimal internal clearance

Accuracy class: SP precision grade

Structure: NN double row design, inner ring with three ribs, ribless outer ring allowing axial floating

Outer ring flange: None

Seal: Open design, no seals

Surface coating: Uncoated

Pre-lubrication: No lubricant supplied from factory

Re-lubrication feature: No circumferential lubrication groove & oil holes on outer ring, continuous on-line re-lubrication not available

Code Explanation

NN: Double row cylindrical roller bearing, three ribs on inner ring, ribless outer ring with axial floating capacity to compensate spindle thermal elongation, mainly applied for radial loads with superior rigidity.

3014: Size series 30 wide cross-section double row spindle bearing with enlarged load capacity for heavy-duty machine tools.

TN: Non-metallic roller-guided cage, low friction and controlled temperature rise.

SP: Precision accuracy grade with strictly controlled rotational runout for medium-high speed heavy-duty precision machine tool spindle applications.

Load & Speed Data

Basic dynamic load rating Cr：96.8 kN

Basic static load rating C0r：150 kN

Permissible speed, grease lubrication：8 000 r/min

Permissible speed, oil-air lubrication：9 000 r/min

Material & Additional Properties

Rolling element material: Bearing steel

Indicative carbon footprint：3.9 kg CO₂e

Net weight：1.05 kg

eClass code：23-05-09-01

UNSPSC code：31171505

Suffix Explanation

NN: Double row cylindrical roller bearing. Three ribs on inner ring guide two rows of rollers; ribless outer ring floats axially to absorb thermal expansion. Primarily suitable for radial loads, rigidity far exceeds single row bearings of identical dimension.

3014: Series 30 wide-section double row spindle bearing with extended contact length, the preferred choice for heavy load conditions.

TN: Non-metallic cage. Light weight reduces friction and temperature rise under medium-high rotation speed.

SP: Precision accuracy grade. Dimensional tolerance, radial and axial runout are tighter than standard bearings to sustain stable precision during continuous heavy cutting.

C1 clearance: Minimal radial internal clearance, matched for lightly preloaded medium-high speed heavy-duty spindle systems to suppress vibration and improve workpiece surface finish.

Important reminder: This straight bore NN-type double row cylindrical roller bearing with steel rollers features fixed preload after mounting without adjustment via lock nut. No W33 circumferential lubrication groove on outer ring, cannot connect to continuous automatic lubrication circuits, only suitable for intermittent production with one-time grease filling during mounting. NN-type floating outer ring bears pure radial loads and cannot withstand axial forces; spindle axial positioning must be undertaken by paired angular contact ball bearings. Open bearing without built-in seals; labyrinth seals or oil seals must be installed on housings to block coolant and dust ingress. No pre-filled grease upon delivery. The double-row structure delivers much higher load capacity and spindle rigidity than N-series single row bearings of equal size at the cost of slightly lower limiting rotational speed. Ideal for heavy cutting finishing applications with stable process parameters without frequent preload adjustment.

Alternative variants:

NN3014 KTNHA/SP (1:12 tapered bore, steel rollers, non-metallic cage, SP C1 clearance, on-site preload adjustable)

NN3014 TN/SPW33 (straight bore, steel rollers, outer ring W33 groove supporting continuous re-lubrication)

NN3014 TN/HC5SP (straight bore, non-metallic cage, composite rollers, higher limiting speed, lower load capacity)

NN3014 TN/UP (straight bore, UP ultra-precision grade for ultra-precision heavy-duty grinding spindles)

2 Structure & Operating Characteristics

NN 3014 TN/SP is an SP-grade precision double row cylindrical roller bearing with C1 minimal radial clearance, TN non-metallic cage, bearing steel rolling elements, straight cylindrical bore and outer ring without lubrication groove. Two rows of steel rollers share loads simultaneously to improve radial rigidity and load limit. The NN design with ribless outer ring allows free axial sliding to automatically compensate spindle thermal expansion and avoid extra axial stress induced by temperature rise.

It adopts straight cylindrical bore structure. Preload is fixed after installation via fit tolerance, suitable for heavy-duty production lines with stable cutting loads requiring no frequent spindle rigidity adjustment. The non-metallic cage controls friction and temperature rise effectively. Without outer ring W33 channel, uninterrupted re-lubrication during running is impossible, only applicable to intermittent processing equipment with scheduled downtime for grease replenishment. Combined C1 minimal clearance and precision manufacturing tolerances suppress rotary vibration at medium-high speeds and guarantee surface quality in precision finishing under heavy loads.

Selection guide:

NN3014 TN/SP (straight bore, steel rollers, non-metallic cage, no W33 groove, SP C1 clearance, fixed preload, heavy load & high rigidity, medium-high speed, intermittent processing with one-time greasing)

NN3014 TN/SPW33 (straight bore, steel rollers with lubrication groove, fixed preload plus continuous on-line lubrication)

NN3014 KTNHA/SP (1:12 tapered bore, steel rollers, adjustable preload for heavy-duty lines with frequent process changes)

NN3014 TN/HC5SP (straight bore, composite rollers, higher limiting speed, weaker load capacity)

NN3014 TN/UP (straight bore, ultra-precision grade for heavy-duty mirror precision grinding)

Recommended matching bearing: Paired 7014 SP angular contact ball bearings to bear all axial loads and realize bidirectional spindle axial positioning.

3 Core Performance Advantages

1. Double-row bearing steel roller arrangement provides powerful radial load capacity and superior spindle rigidity for heavy cutting operations.

2. NN-type double-row wide-section structure achieves uniform load distribution and better anti-tilting performance than single row cylindrical roller bearings.

3. Straight cylindrical bore enables simple assembly, stable fit and permanent fixed preload for convenient maintenance.

4. Lightweight TN non-metallic cage lowers friction loss and suppresses temperature rise during medium-high speed operation.

5. SP precision standard combined with C1 minimal radial clearance delivers tight control over rotational runout, mitigates vibration and stabilizes machining accuracy and surface finish under heavy cutting loads.

6. Axially floating outer ring automatically compensates spindle thermal elongation and prevents abnormal additional stress inside the bearing.

4 Typical Application Fields

4.1 Spindle units of heavy-duty vertical machining centers

Heavy cutting, fixed workpiece types without frequent spindle preload adjustment, intermittent production without 24-hour automatic continuous lubrication

4.2 Medium-high speed CNC cylindrical & internal heavy-duty grinding precision spindles

Stable heavy-load grinding, long-term continuous finishing, periodic shutdown maintenance for grease filling

4.3 Heavy-load precision CNC lathes and turn-mill composite spindles

Mixed finishing, semi-finishing and heavy cutting, steady loads with unchanged process parameters

4.4 General heavy-duty medium-high speed precision rotary spindle equipment

Large radial loads, high requirements on spindle rigidity and load stability, without uninterrupted automatic oil supply circuit

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

SP precision bearings should be assembled in constant-temperature dust-free clean workshops. Thoroughly remove contaminants on shaft journals, housing bores and spacer contact surfaces. Preload is determined by fit tolerance for straight bore bearings; calculate dimensional tolerance accurately before assembly. No lubrication groove on outer ring; grease can only be filled during assembly, formulate regular shutdown maintenance plan for supplementary greasing. Reliable sealing must be installed on machine housings to prevent coolant and dust from reaching rolling surfaces. This NN-type bearing cannot withstand axial loads, paired angular contact bearings are mandatory for spindle axial positioning. Although double-row rollers offer strong load capacity, avoid long-term continuous extreme shock loads.

5.2 Selection Guidance

Medium-high speed, stable heavy load, fixed process without preload adjustment, intermittent production, no continuous on-line oil supply → NN3014 TN/SP

Stable process equipped with continuous automatic lubrication, medium-high speed steady heavy load operation → NN3014 TN/SPW33

Frequent process changes requiring on-site preload adjustment, heavy cutting loads → NN3014 KTNHA/SP

Higher limiting speed priority, medium load → NN3014 TN/HC5SP

Ultimate rotational accuracy, heavy-duty mirror grinding → NN3014 TN/UP

Important notice: No outer ring lubrication groove for this model, lubricant cannot be replenished while equipment is running, periodic maintenance schedule is mandatory. NN double row structure is designed purely for radial loads; continuous accidental axial force triggers edge stress concentration, roller scuffing and premature fatigue failure.

5.3 Lubrication Maintenance Instruction

No lubricant pre-filled at factory. Oil-air lubrication is recommended to achieve maximum permissible rotational speed; grease one-time filling is adopted for intermittent working conditions. Lacking outer ring oil groove, grease cannot be supplemented into bearing without machine shutdown. Set maintenance cycle according to operating conditions, shut down periodically to disassemble end caps for re-greasing; prevent premature wear caused by long-term insufficient lubrication. Continuously monitor bearing temperature. Stop operation immediately once abnormal temperature rise occurs to inspect lubrication status and fit clearance. Compared with N1014 single row bearing of identical size, heat generation is higher at the same rotational speed, so stricter lubrication management is required.

5.4 Environmental Application Notes

Open structure without built-in seals; labyrinth seals or oil seals on housings are compulsory. Rolling contact surfaces are extremely sensitive to tiny hard particles. Contamination amplifies vibration and rapidly deteriorates machining accuracy. Double-row rollers feature longer contact lines, and pitting damage caused by impurities expands more easily, therefore higher standards for dust and coolant protection are required than single row bearings. Bearing steel rollers provide excellent load and shock resistance, yet long-term operation under high temperature accelerates grease ageing, so operating temperature should be controlled within reasonable range.

6 Fault Identification

Common failure modes: steadily rising vibration during heavy cutting, regular texture patterns on machined workpieces, abnormal continuous spindle temperature increase, periodic rotational noise, cage abrasion & deformation, scuffing of rolling elements and raceway fatigue spalling. Typical failures for straight bore double row bearings: improper selection of shaft fit tolerance leads to persistent overheating due to over-tight fit or obvious rigidity degradation due to loose fit; premature wear due to aged and exhausted grease without online replenishment; uneven abrasion of two roller rows induced by unexpected axial loads; raceway spalling caused by long-term overload and shock loads. Shut down equipment immediately upon persistent abnormal noise or irreversible accuracy degradation. Bearings with permanent damage to raceways, rolling elements or cage cannot be repaired and need complete replacement.