NTN bearing “tolerances” or dimensional accuracy and running accuracy, are regulated by ISO and JIS B 1514 standards (rolling bearing tolerances). For dimensional accuracy, these standards prescribe the tolerances necessary when installing bearings on shafts or in housings. Running accuracy is defined as the allowable limits for bearing runout during operation.
Dimensional accuracy
Dimensional accuracy constitutes the acceptable values for bore diameter, outer diameter, assembled bearing width, and bore diameter uniformity as seen in chamfer dimensions, allowable inner ring tapered bore deviation and shape error. Also included are, average bore diameter variation, outer diameter variation, average outer diameter unevenness, as well as raceway width and height variation (for thrust bearings).
Running accuracy
Running accuracy constitutes the acceptable values for inner and outer ring radial runout and axial runout, inner ring side runout, and outer ring outer diameter runout.
Allowable rolling bearing tolerances have been established according to precision classes. Bearing precision is stipulated as JIS class 6, class 5, class 4, or class 2, with precision rising from ordinary precision indicated by class 0.
| Bearing type | Applicable standard | Tolerance class | Tolerance table | |||||
|---|---|---|---|---|---|---|---|---|
| NTN Deep groove ball bearings |
JIS B 1514 (ISO492) |
class 0 | class 6 | class 5 | class 4 | class 2 |
tolerances for radial bearings (normal, P6, P5) |
|
| Angular contact ball bearings | class 0 | class 6 | class 5 | class 4 | class 2 | |||
| Self-aligning ball bearings | class 0 | - | - | - | - | |||
| Cylindrical roller bearigns | class 0 | class 6 | class 5 | class 4 | class 2 | |||
| Needle roller bearings | class 0 | class 6 | class 5 | class 4 | - | |||
| Spherical roller bearings | class 0 | - | - | - | - | |||
| NTN Tapered roller bearings | metric | JIS B 1514 | class 0,6X | class 6 | class 5 | class 4 | - | Tolerance of tapered roller bearings |
| Inch | ANSI/ABMA Std.19 | class 4 | class 2 | class 3 | class 0 | class 00 | ||
| J series | ANSI/ABMA Std.19.1 | class K | class N | class C | class B | class A | ||
| Thrust ball bearings |
JIS B 1514 (ISO199) |
class 0 | class 6 | class 5 | class 4 | - | Tolerance of thrust ball bearings | |
| Spherical roller thrust bearings | class 0 | - | - | - | - | |||
| Standard | Applicable standerd | Tolerance Class | Bearing Types | ||||
|---|---|---|---|---|---|---|---|
| Japanese industrial standard (JIS) | JIS B 1514 | Class 0,6X | Class 6 | Class 5 | Class 4 | Class 2 | All type |
| International Organization for Standardization (ISO) | ISO 492 | Normal class Class 6X | Class 6 | Class 5 | Class 4 | Class 2 | Radial bearings |
| ISO 199 | Normal Class | Class 6 | Class 5 | Class 4 | - | Thrust ball bearings | |
| ISO 578 | Class 4 | - | Class 3 | Class 0 | Class 00 | Tapered roller bearings (Inch series) | |
| ISO 1224 | - | - | Class 5A | Class 4A | - | Precision instrument bearings | |
| Deutsches Institut fur Normung(DIN) | DIN 620 | P0 | P6 | P5 | P4 | P2 | All type |
| American National Standards Institute (ANSI) | ANSI/ABMA Std.20 |
ABEC-1 RBEC-1 |
ABEC-3 RBEC-3 |
ABEC-5 RBEC-5 |
ABEC-7 | ABEC-9 |
Radial bearings (Except tapered roller bearings) |
| American Bearing Manufacturer's Association (ABMA) | ANSI/ABMA Std.19.1 | Class K | Class N | Class C | Class B | Class A | Tapered roller bearings (Metric series) |
| ANSI/ABMA Std.19 | Class 4 | Class 2 | Class 3 | Class 0 | Class 00 | Tapered roller bearings (Inch series) | |