Know It All: N and NN Super Precision Cylindrical Roller Bearings
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Product: Super Precision Cylindrical Roller Bearings
Short: SP CRB
Prefix: N single row and NN double row
ISO size: N 10 or NN 30
Roller Type: Cylindrical
Roller Material: Steel or Ceramic
Direction: Radial
Position: Non-locating
Separable: Y
Bore: Straight or Tapered
Cage: Brass (finger type), Polyamide (pocket type), or PEEK
Clearance: C1, C2, Special
Seals: no
Relive: groove and holes in outer ring in NN series optional
Tolerances: SP class 5 dimensions with Class 4 runout, or UP class 4 dimensions with Class 4 runout,
Applications: Spindle, Machine Tool, Grinding, Threading
Starting Bore Code range: 06 (30mm)
Common sizes: N1011, N1012, N1013, N1014, N1017, N1022, N1038, NN3006,
NN3007,
NN3008,
NN3010,
NN3011,
NN3012,
NN3013,
NN3014,
NN3015,
NN3016,
NN3017,
NN3018,
NN3020,
NN3021,
NN3022,
NN3026,
NN3030,
NN3032,
NN3040,
NN3044
Intro
Super Precision Cylindrical Roller Bearings of series N10xx and N30xx are top of the line rolling bearings known for runout control, rigidity, and high load ratings. Top manufacturers include SKF, Schaeffler FAG, NSK, and NTN. The non-locating design makes these bearings ideal for float (expansion) positions and are usually paired with high contact angle axial thrust ball bearings like Schaeffler FAG’s double direction 2344 series or a pair of single row bearings in main spindles, threading machines, printing machines, and other machine tool.
Clearance
Radial internal clearance range is C1 as standard, while manufacturers can specify smaller or larger classes, or specific ranges.
Bore
Tapered bores of “K” suffix with 1:12 taper designed for mounting on tapered shafts allow assemblers to drive the inner ring and roller assembly axially up the taper. This process, including the precise axial drive up distance, is used to set internal clearance in the bearing position when mated with the outer ring. With straight bore bearings, mounted clearance is set by bench clearance of the bearing and the fits on the shaft and housing. Minimizing internal clearance during operation increases the load zone and load distribution, roller stability, and operating life.
R&D
With the ever expanding requirements of machinery and tools to run faster, longer, and with less maintenance, manufacturers have turned to additional finishing processes of raceways, including honing, to reduce friction and increase limiting speeds. Known for durability and precision, Schaeffler FAG revised their line up to bore code 24 to include their x-life quality and lightweight TVP polyamide cages which delivered higher speeds and load ratings. NTN specializes in high speed applications, offering both HS high speed and HSR ultra high speed designs. HS designs use lightweight brass cages and honed rolling surfaces, while their HSR design adds a PEEK cage, a material known for low weight, high strength, and high stability. Manufacturers have also turned to ceramic cylindrical rollers to create hybrid bearings, with benefits matching those of hybrid ceramic ball type spindle bearings: speed, lower friction, lower temperatures, less deflection, and better mixed friction (inadequate lubrication) operating conditions.
Additional Features
SKF offers inspection services and reports on new bearings to identify the exact dimensions and internal clearance of a single bearing. This allows assemblers to dial in fits on shaft and housing, and the resulting mounted clearance, when grinding components without relying on tolerance ranges. This decreases the time required to mount bearings and increases the accuracy of the setup.
Look Out For
Bearings from one manufacturer are interchangeable with those from another manufacturer, but pay special attention to the lubrication method and limiting speed of your existing set up. These SP CRB are available with or without a oil groove and holes in the OD for relubrication, which is specified with a W33 (from SKF) or AS (from Schaeffler FAG). If you lubricate through the outer ring, make sure your bearing has this feature. Regarding operating speed, honed raceways and lightweight cages usually push the limiting speed upwards by 25-40% (i.e. 5000 RPM to 7000RPM) while maintaining the dynamic load ratings. These lightweight polyamide or PEEK cages are lightweight and capable at speed, but more prone to damage due to impact and less rigid compared to the M brass cages.
Shop
Check out of selection of premium brand, new in box super precision cylindrical roller bearings available at: https://borecode.com/collections/super-precision-cylindrical-roller-bearings
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- Etiquetas: CNC, CRB, cylindrical roller bearing, fag, Machine, machine tool, nsk, ntn, skf, SP CRB, Spindle
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