Bearing manufacturing process: 1. Bearing material: 1. Bearing steel: high carbon iron bearing steel (SUJ2 → small steel; SUJ3 → large steel; SUJ4 → special steel;) 2. Accuracy requirements: international standard 01. Inner diameter tolerance : Φ20 or more, 0~10um2. Outer diameter tolerance: 0~10um3. Thickness tolerance: 0~120um, generally 30~40 Note: The larger the inner diameter, the larger the outer diameter tolerance. 3. Bearing toughness treatment: 1. Surface hardness of inner and outer rings: HRC: 58～62°2. Surface hardness of steel ball: HRC: 60～64°4. Code identification (see book A48) 1. As shown in the figure: 2. Inner diameter dimension ⅲHe color above 04 must be u003d last 2 digits * 5, the inner diameter size of mantissa below 04 is special, as follows: 03u003du003d17 02u003du003d15 01u003du003d12 00u003du003d10 The front is the code, the back is It is the inside diameter size. 3. The code of the sealing plate is as follows: the sealing plate is divided into iron sealing ring and rubber sealing ring. (See book A50) Z stands for single-sided dust cover ZZ stands for double-sided dust cover ZX stands for single-sided dust cover (with spring retaining ring) ZZX represents double-sided dust cover (with spring retaining ring) RU stands for single-sided Contact seal 2RU stands for double-sided non-contact seal RS stands for single-sided contact seal 2RS stands for double-sided contact seal RD stands for single-sided ultra-light contact seal 2RD stands for double-sided ultra-light contact seal ZU 2ZU (non-contact seal ring) RK 2RK U UU (contact seal ring) 4. The clearance code is as follows: (see book A50) CN stands for standard clearance C2 CM CN C3 C4 C5 C2 is less than the standard clearance CM is greater than C2 Standard clearance CN Standard clearance C3 Clearance for high temperature C4 and C5 should be specially made 5b ferrule shape code (see book A50) Oil groove oil hole code: K stands for tapered hole inner ring (K 1:12) K30 stands for Tapered bore inner ring (K 1:30) N stands for bearing with stop groove on the outer surface NR stands for bearing with stop groove and stop ring on the outer circle NY stands for bearing with anti-creep synthetic resin ring Sub bearing inner surface with spiral groove W Cylindrical roller bearing outer surface with oil groove and oil hole W33 Spherical roller bearing outer surface>Oil groove and oil hole Note: For other codes, see page A50 of KOYO product book. 5. Product model (the first two digits of the model, such as the beginning of 68, represent single-row deep groove ball bearings): (see book A49) bearings are called hair, cylindrical roller bearings (CRB), tapered roller bearings (TRB), needle roller bearings ( NRB), spherical roller bearing (SRB), deep groove ball bearing (SBB) (1) Single row deep groove ball bearing: 68 69 160 60 62 63 64 (2) Double row deep groove ball bearing: 42 43 (3) Single row angular contact ball bearing: 79 70 72 73 74⑷ Double row angular contact ball bearings: (32 33 have n grooves) 52 53⑸ Self-aligning ball bearings: 12 22 13 23 112 113⑹ Single row cylindrical roller bearings: NU10 NU2 NU22 NU32 NU3 NU23 NU4⑺ Double row cylindrical roller bearings : NNU49 NN30⑻ single row needle roller bearings: NA48 NA49 NA59⑼ double row needle roller bearings: NA69⑽ tapered roller bearings: 329 320 330 331 302 322 332 303 313 323⑾ Spherical roller bearings: 239 230 240 231 241 223⑿ one-way Plane thrust ball bearings: 511 512 513 514⒀ One-way self-aligning thrust ball bearings: 532 533 534⒁ Two-way plane thrust ball bearings: 522 523 524⒂ Two-way self-aligning thrust ball bearings: 542 543 544⒃ Thrust spherical roller bearings: 292 293 294