What Are Our Concerns About Bearings（32）

Q1: How to explain the bearing category?

Double row angular contact ball bearings  

1. Self-aligning ball bearing  

2 self-aligning roller bearing and thrust self-aligning roller bearing  

Tapered roller bearing  

Double row deep groove ball bearings  

Thrust ball bearing  

6 deep groove ball bearings  

7 Angle contact bearings  

Thrust cylindrical roller bearing  

N Cylindrical roller bearing and double row cylindrical roller bearing NN  

U Outer spherical bearing  

QJ four point contact ball bearing  

In addition, there are front and rear bearing codes before and after the bearing code, as follows:  

— precode  

The front code R is placed directly before the bearing basic code, and the rest codes are separated from the basic code by small dots.  

GS. — Thrust cylindrical roller bearing ring.  Example: GS. 81112.  

K. — combination of rolling body and cage.  Example: thrust cylindrical roller and cage assembly K.81108  

R — Bearings without detachable inner or outer rings.  Example: RNU207 — NU207 bearing without inner ring.  

WS — Thrust cylindrical roller bearing ring.  Example: the WS. 81112.  

— Interior design  

— Shape size and deformation design  

– seal  

– keep frame  

– the tolerance  

– clearance  

– heat treatment  

— Special design  

— Machine tool spindle bearing  

— Low noise and saving bearing  

— Postcode  

The postcode is placed after the base code.  When there are multiple groups of rear codes, they should be arranged from left to right in the order of the rear codes listed in the bearing code table.  Some postcodes are preceded by dots from the base code.  

Postcode – Internal structure  

A, B, C, D, E — Internal structural changes  

Example: Angular contact ball bearings 7205C, 7205E, 7205B, C — 15 ° contact Angle,E — 25 ° antenna, B — 40 ° contact Angle.  

Example: Cylindrical roller, self-aligning roller and thrust self-aligning roller bearings N309E, 21309E, 29412E — enhanced design, bearing load capacity increased.  

VH — Full roller cylindrical roller bearing with self-locking roller (the diameter of the compound circle of the roller is different from the standard bearing of the same type).  

Example: NJ2312VH.  

Rear code – bearing dimensions and external structure  

DA — Separable double row angular contact ball bearings with double half inner rings.  Example: 3306 da.  

DZ — roller bearing with cylindrical outer diameter.  Example: ST017DZ.  

K — Tapered bore bearing, taper 1:12.  Example: 2308 k.  

K30- Tapered bore bearing, taper 1:30.  Example: 24040 K30.  

2LS — Double row cylindrical roller bearings with double inner rings and dust cover on both sides.  Example: NNF5026VC.2Ls.v — Internal structure change, double inner rings, with dust cover on both sides, double row cylindrical roller bearing with full roller.  

N — bearing with stop groove on outer ring.  Example: 6207 n.  

NR — Bearing with stop groove and stop ring on outer ring.  Example: 6207 NR.  

N2- – Four-point contact ball bearing with two stop grooves on the outer ring.  Example: QJ315N2.  

S — bearing with oil grooves and three oil holes in the outer ring.  Example: 23040 S.  Self-aligning roller bearings with bearing outer diameter D ≥ 320mm are not marked with S.  

X — Dimensions in line with international standards.  Example: 32036 x  

Z•• — Technical conditions for special structures.  Starting at Z11 and going down.  Example: Z15 — Stainless steel bearing (W-N01.3541).  

ZZ — a retaining ring with two outer rings for roller bearings.  

Rear code – sealed and dust-proof  

RSR — Bearing side with sealing ring.  Example: 6207 RSR  

.2RSR — Bearing with sealing rings on both sides.  Example: 6207.2 RSR.  

ZR — Bearing with dust cover on one side.  Example: 6207 ZR  

.2ZR bearing with dust cover on both sides.  Example: 6207.2 ZR  

ZRN — Bearing with dust cover on one side and stop groove on the other outer ring.  Example: 6207 ZRN.  

2ZRN — Bearing with dust cover on both sides, with stop groove on the outer ring.  Example: 6207.2 ZRN.  

Rear code – Cage and its materials  

1 Physical cage.  

A or B is placed after the cage code, where A indicates that the cage is circled outside and B indicates that the cage is circled inside.  

F — Steel solid cage, rolling body.  

FA — Steel solid cage, outer ring.  

FAS — Steel solid cage, outer ring, with lubrication groove.  

FB — Steel solid cage, inner ring.  

FBS — Steel solid cage, inner ring, with lubrication groove.  

FH — Steel solid cage, carburized and hardened.  

H, H1 — Carburizing and quenching retainer.  

FP — Steel solid window cage.  

FPA — Steel solid window cage with outer ring.  

FPB — Steel solid window cage, inner ring.  

FV, FV1 — Steel solid hole cage, aged and tempered.  

L — Light metal solid cage, rolling body.  

LA — Light metal solid cage, outer ring.  

LAS — Light metal solid cage, outer ring, with lubrication groove.  

LB — Light metal solid cage, inner ring.  

LBS – Light metal solid cage, inner ring, with lubrication groove.  

LP — Light metal solid window cage.  

LPA — Light metal solid window cage, outer ring.  

LPB — Light metal solid window cage, inner ring (thrust roller bearing as shaft).  

M, M1 — Brass solid cage.  

MA — Solid brass cage, outer ring.  

MAS — Solid brass cage, outer ring, with lubrication groove.

MB — Brass solid cage, inner ring (thrust self-aligning roller bearing as shaft ring).  

MBS — Solid brass cage, inner ring, with lubrication groove.  

MP — Brass solid straight pocket holder.  

MPA — Brass solid straight pocket also retainer, outer ring.  

MPB — Brass solid straight pocket holder, inner ring.  

T — Phenolic laminate tube solid cage, rolling body.  

TA — Phenolic laminate tube solid holder, outer ring.  

TB — Phenolic laminate tube solid cage, inner ring.  

THB — Phenolic laminate pipe pocket cage, inner ring.  

TP – Phenolic laminate tube straight pocket holder.  

TPA — Phenolic laminate pipe straight pocket holder, outer ring.  

TPB — Phenolic laminate tube straight pocket holder, inner ring.  

TN — Engineering plastic mold injection cage, rolling body, with additional numbers for different materials.  

TNH — Engineering plastic self-locking pocket cage.  

TV — Glass fiber reinforced polyamide solid retainer, steel ball.  

TVH — Glass fiber reinforced polyamide self-locking pocket solid cage, steel ball.  

TVP — Glass fiber reinforced polyamide window solid cage, steel ball.  

TVP2 — Glass fiber reinforced polyamide solid cage, roller.  

TVPB — Glass fiber reinforced polyamide solid cage, inner ring (thrust roller bearing as shaft).  

TVPB1 — Glass fiber reinforced polyamide solid window cage, shaft (thrust roller bearing).  

Punch cage  

J — Steel plate stamping cage.  

JN — Riveting cage for deep groove ball bearing.  

Cage change  

The number added after or inserted in the cage code indicates that the cage structure has been changed.  These numbers are only used for transitional periods, for example NU 1008M 1.  

Rear code – no cage bearing  

V — Fully loaded rolling bearing.  Example: NU 207V.  

VT — Fully loaded rolling bearing with isolation ball or roller.  Example: 51120 n.  

Rear code — Tolerance class (dimensional accuracy and rotation accuracy)  

P0 — Tolerance class in accordance with the international standard ISO level 0, code omitted, does not indicate.  

P6 — Tolerance grade in accordance with ISO level 6.  

P6X — Grade 6 tapered roller bearings with tolerance class in accordance with international standard ISO.  

P5 — Tolerance class in accordance with the international standard ISO level 5.  

P4 — Tolerance grade in accordance with international standard ISO level 4.  

P2 — Tolerance class in accordance with international standard ISO class 2 (excluding tapered roller bearings).  

SP — Dimensional accuracy is equivalent to class 5 and rotation accuracy is equivalent to class 4 (double row cylindrical roller bearings).  

UP — Dimensional accuracy is equivalent to grade 4, and rotational accuracy is higher than grade 4 (double row cylindrical roller bearings).  

HG — Dimensional accuracy equivalent to grade 4, rotation accuracy higher than grade 4, lower than grade 2 (spindle bearing).  

Rear code – clearance  

C1 — Clearance in accordance with the standard 1 group, less than 2 groups.  

C2 — 2 groups of clearance in accordance with the standard, less than 0 group.  

C0 — Group 0 of clearance in accordance with the standard, code omitted, does not represent.  

C3 — 3 groups of clearance in accordance with the standard, greater than 0 group.  

C4 — Clearance in accordance with the standard of 4 groups, greater than 3 groups.  

C5 — Clearance in accordance with the standard of 5 groups, greater than 4 groups.  

When tolerance class code and clearance code need to be expressed at the same time, the combination of tolerance class code (P0 is not indicated) and clearance group number (0 is not indicated) is taken.  

Example: P63=P6+C3, indicating bearing tolerance grade P6, radial clearance 3 groups.  

P52=P5+C2, indicating bearing tolerance grade P5, radial clearance 2 groups.  

For non-standard clearance, where special radial and axial clearance are required, the limit values concerned shall be expressed as A number of μ m after the letter R (radial clearance) or A (axial clearance), separated by small dots.  

Example: 6210.R10.20 — 6210 bearings, radial clearance 10 μ m to 20 μ m.  

Bearings A120.160 — 6212, Axial clearance 120 μ m to 160 μ m  

Rear code – bearings for testing noise  

F3 — Low noise bearing.  It mainly refers to cylindrical roller bearings and deep groove ball bearings with inner diameter D > 60mm and above.  Example: 6213. The F3.  

G — Low noise bearing.  It mainly refers to deep groove ball bearings with inner diameter D ≤ 60mm.  Example: 6207 G

Post code — heat treatment  

S0 — Bearing ring after high temperature tempering treatment, the working temperature can reach 150 ℃.  

S1 — The bearing ring is tempered at high temperature and the working temperature can reach 200 ℃.  

S2 — Bearing ring after high temperature tempering treatment, the working temperature can reach 250 ℃.  

S3 — Bearing rings are tempered with high temperature, and the working temperature can reach 300 ℃.  

S4 — Bearing rings are tempered at high temperature to work at 350 ℃.  

Postcode — Special technical condition  

F•• — Manufacturing technical conditions for serial numbering.  Example: F80 — bearing inner and outer diameter tolerances and radial clearance compression.  

K•• — Technical requirements for continuous numbering.  Example K5 — bearing tolerance compression of inner and outer diameters.  

.ZB — cylindrical roller with convex diameter greater than 80mm.  Example: NU 364.zb.  

ZB2 — The crown at both ends of the needle roller is greater than the general technical requirements.  Example: K18 × 26 × 20F.zB2.  

ZW — Double row needle roller and cage assembly.  Example: K20 × 25 × 40FZW.  

.700•• — Technical conditions for serial numbers beginning with 700000.  

Z52JN.790144 — Bearings can be used for high temperature and low speed, after special heat treatment, steel plate stamping riveting cage, large clearance, phosphating treatment, grease injection, the service temperature can exceed 270 ℃.  

Postcode — Special technical condition  

KDA – the Split inner ring /;  Split inner ring  

K — Tapered bore 1:12  

K30 — Tapered bore 1:30  

N — Circular in the outer ring for snap ring  

S — What about groove and bores in the outer ring  

The “S” suffix has been completely removed in the new E1 series!  Outer ring filling groove and oil hole are now standard.  

W03B Stainless steel bearing  

N2 two retaining troves for fixing the outer ring  

Two stop grooves for stop outer rings  

Rear code – pair bearings and machine tool spindle bearings  

1) Pairs of bearings that meet K technical conditions, and the following special technical conditions are related to pairs of bearings:  

K1 — Two sets of deep groove ball bearings are mounted in pairs to withstand unidirectional axial loads.  

K2 — Two sets of deep groove ball bearings are mounted in pairs to withstand bidirectional axial loads.  

K3 — Two sets of deep groove ball shafts are installed back-to-back with no clearance (O-type installation).  

K4 — Two sets of deep groove ball bearings are installed face to face with no clearance (type X).  

K6 — Two sets of angular contact ball bearings are mounted in pairs to withstand unidirectional axial loads.  

K7 — Two sets of angular contact ball bearings are mounted back to back with no clearance (O-type mounting).  

K8 — Two sets of angular contact ball bearings are mounted face to face without clearance (TYPE X)  

K9 — Two sets of tapered roller bearings with compartments between inner and outer rings are mounted in pairs to withstand unidirectional axial loads.  

K10 — Two sets of tapered roller bearings with ring between inner and outer rings mounted back to back without clearance (TYPE O mounting)  

K11 — Two sets of tapered roller bearings with a ring between the outer rings are installed face to face without clearance (type X installation).  

Bearings in pairs or groups need to be packaged together for delivery or marked as belonging to a pair.  Different sets of bearings are not interchangeable.  When installing bearings belonging to the same group, the installation should be carried out in accordance with marks and positioning lines.  If pairs of bearings are configured according to a certain axial or radial clearance amount, their clearance shall be indicated after K technical condition according to article 1 (2) of Item (7).  For example, 31314A.k11.A100.140 represents two sets of 31314A single row tapered roller bearings, mounted face to face, with a certain distance between the outer rings, bearing assembly front axial clearance between 100 μ m and 140 μ m, after assembly clearance is zero.  

General purpose pair bearing  

Can be installed in any pair (series, face to face or back to back), after code UA, UO and UL.  

UA — Small axial clearance when bearings are mounted face to face or back to back.  

UO — No clearance when bearing is installed face to face or back to back.  

.ul — Slight pre-interference when bearings are installed face to face or back to back.  For example, b7004C.tPA.p4.k5.ul  

Represents angular contact ball bearing with contact Angle of 15O for spindle, phenolic laminate pipe straight pocket solid retainer, outer ring, bearing tolerance class 4, reduced inner and outer diameter tolerance, universal construction mounted in pairs, bearing with slight pre-interference when mounted back to back or face to face  

Rear code – machine tool spindle bearing  

KTPA.HG Clamp with this pocket solid cage, outer ring, accuracy grade HG.  Tpa.hg.k5.UL Clamp cloth to meet this pocket solid cage, outer ring, accuracy grade HG, bearing tolerance reduction of outer and inner diameters, all-body structure mounted in pairs, bearing with slight interference when mounted face to face or back to back.  

Tpa.p2.k5.UL Clamp fabric with this pocket solid cage, outer ring, accuracy grade HG, bearing tolerance reduction of outer and inner diameters, all-body structure mounted in pairs, bearing with slight interference when mounted face to face or back to back.  

Tpa. P2 UL Clamp fabric to this pocket solid cage, outer ring, accuracy class HG, bearing tolerance reduction of outer and inner diameters, full-body structure mounted in pairs, bearing with slight interference when mounted face to face or back to back.  

Rear code – machine tool spindle bearing  

Tpa.p2.k5.UL Clamp fabric Solid cage with pocket holes, outer ring, accuracy class HG, general construction for mounting in pairs, bearing with slight interference when mounted face to face or back to back.  

C coulact Angle/contact Angle 15 “C  

D coulact Angle/contact Angle 25 “C