1 Model Information & Technical Parameters

Model：NN 3005/SP

Dimensions

Bore d：25 mm

Outer diameter D：47 mm

Width B：16 mm

Bore type: Straight cylindrical bore

Code Explanation

NN: Double row cylindrical roller bearing, inner ring double ribs, outer ring ribless, separable inner and outer rings

3005: Size series 30, size code 05, nominal bore 25 mm

/SP: Super precision tolerance class, higher accuracy than standard P4 for spindle applications

Load Characteristics

Permitted load: Radial load only; axial load capacity is extremely low

Structure: Separable construction, inner ring with double ribs; solid brass cage guides rollers

Limiting speed: Subject to lubrication mode; oil-air lubrication enables higher rotational speed than grease lubrication

Pre-grease: No pre-filled grease supplied, lubricant added during installation

Logistics & Industry Codes

Net weight：0.13 kg

Indicative carbon footprint：0.20 kg CO₂e

eClass code：23-05-09-01

UNSPSC code：31171505

Suffix Explanation

NN: Double row cylindrical roller bearing without ribs on outer ring. Inner and outer rings can be separated for convenient assembly and inspection. Rollers are restrained by inner ring ribs.

No suffix K: Straight cylindrical bore without 1:12 taper. Preload cannot be adjusted by expanding inner ring axially; preload is preset via fit tolerance or spacer sleeves.

/SP: Super precision spindle grade. Strict control of raceway geometry and rotational runout to satisfy finishing and grinding spindle requirements.

Important reminder: The ribless outer ring cannot withstand axial force independently. Spindle system must be equipped with matched precision angular contact ball bearings to carry axial load. Preload cannot be tuned on site for straight bore design. Dimension chain including shaft, housing bore and spacers must be accurately calculated in advance. Hammer impact installation is prohibited; thermal mounting is recommended. Taper bore adjustable alternative: NN3005 K/SP. General precision alternative: NN3005/P4. Higher precision option: NN3005/UP.

2 Structure & Operating Characteristics

NN 3005/SP super precision double row cylindrical roller bearing adopts two parallel roller rows for superior radial rigidity. Straight bore delivers simple construction, ideal for standardized, mass-produced modular spindle units. SP precision machining reduces rotational runout to guarantee stable machining accuracy. Separable inner and outer rings facilitate spindle disassembly and maintenance.

Selection reference:

NN3005/SP (straight bore + SP super precision, preset preload for standardized spindles)

NN3005 K/SP (1:12 tapered bore + SP super precision, on-site adjustable preload)

NN3005/P4 (straight bore P4 precision, cost effective for general precision machinery)

NN3005/UP (straight bore UP ultra-precision for jig grinders and optical processing equipment)

N/NJ/NF single row bearings: Lower radial rigidity than NN double row series

7005 angular contact ball bearings: Matched to bear spindle axial loads.

3 Core Performance Advantages

1. Double-row roller layout provides large radial load capacity and high radial rigidity to suppress spindle radial deformation.

2. Standard straight bore features simple structure, compatible with standardized modular spindle units for mass production.

3. SP super precision grade achieves minimal rotational runout for high-precision cutting and grinding processes.

4. Separable inner and outer rings enable easy disassembly to simplify spindle maintenance and replacement.

5. Capable of medium-to-high speed operation with proper lubrication for precision spindle transmission systems.

4 Typical Application Fields

4.1 Standardized Precision Machine Tool Spindle Units

Mass-production CNC lathe spindles, vertical machining center spindles, cylindrical and internal grinder spindles

4.2 High-precision rotary equipment with preset preload structure

Precision dividing heads, rotary mechanisms for gear grinders, standardized precision rotary tables

4.3 High radial rigidity, medium-high speed rotary mechanisms without requirement of on-site preload adjustment

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

Precision bearing assembly needs clean and dust-free environment. All mating components must be thoroughly cleaned to remove chips and contaminants. Thermal mounting is recommended for straight bore bearings; striking bearing end face is forbidden. Preload is realized by spacer sleeves or fit tolerance; dimension chain verification shall be completed before assembly. Perform no-load temperature run-in after installation. Geometric tolerances of shaft journal and housing bore must meet requirements for SP grade precision bearings.

5.2 Selection Guidance

Mass-produced standardized precision spindles, preload pre-designed, no on-site adjustment → NN3005/SP

On-site fine-tuning of preload required during assembly → NN3005 K/SP

Medium precision requirement, cost control priority → NN3005/P4

Ultra-precision processing equipment with extreme accuracy demand → NN3005/UP

Significant axial load exists: Combine this bearing with matched 7005 series precision angular contact ball bearings.

5.3 Lubrication Maintenance Instruction

No lubricant pre-filled from factory. High-speed bearing grease for medium-low speed; oil-air lubrication preferred for high-speed spindles. Long-term oil bath lubrication is not recommended. Monitor operating temperature continuously; steady-state temperature rise shall be controlled within 25K. Sustained temperature increase requires inspection of preload and lubrication supply.

5.4 Environmental Application Notes

No built-in seals. The spindle assembly must install oil seals or labyrinth seals to block coolant and dust ingress. Long-term axial load and shock load are forbidden; shock indentations on rollers will permanently damage bearing precision.

6 Fault Identification

Common failure modes: Abnormally high operating temperature, growing spindle radial runout, periodic abnormal noise, raceway indentations, roller fatigue spalling. Stop equipment immediately once precision declines or continuous abnormal noise appears. Damaged precision bearings with flaws on raceways or rollers cannot be repaired and need full replacement.