Accuracy or Precision Grade

There are two types of precision for Ball Bearings. one is dimensional accuracy and the other is rotational accuracy. The standards that control both are written by JIS and ABMA. NMB uses JIS B1514 (ISO 492), ABMA Standard 12-2 and Standard 20. The following symbols are used in this cataloge:

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Symbol

1. Dimensions d Nominal Bore Diameter D Nominal Outside Diameter B Nominal Inner Ring Width C Nominal Outer Ring Width r Chamfer Dimension of Inner Ring or Outer Ring 2. Dimensional Differences Δds Dimensional difference of bore diameter Δdmp Dimensional difference of mean bore diameter in the plane (Δdm)  Dimensional difference of mean bore diameter ΔDs  Dimensional difference of outside diameter ΔDmp Dimensional difference of mean outside diameter in the plane (ΔDmp) Dimensional difference of mean outside diameter ΔBs Dimensional difference of inner ring width ΔCs Dimensional difference of outer ring width ΔD1s Deviation of a single flange outside diameter ΔC1s Deviation of a single width of the outer ring flange

3. Limit Values of Chamfer/Radius Dimension rs min Minimum dimension limit of inner ring and outer ring chamfer rs max Maximum dimension limit of inner ring and outer ring chamfer 4. Inequality of Dimensions Vdp Inequality of bore diameter in a plane Vdmp Inequality of mean bore diameter in a plane VDp Inequality of outside diameter in a plane VDmp Inequality of mean outside diameter in a plane VBs Inequality of inner ring width VCs Inequality of outer ring width VCIs Inequality of flanged width 5. Rotation Precision Kia(Ki) Radial runout of inner ring Sia(Si) Axial runout of inner ring Sd(Sdi) Side runout of inner ring Kea(Ke) Radial runout of outer ring Sea(Se) Axial runout of outer ring SD(SD) Side runout of outer ring Seal Chamfer Dimension of Radial Ball Bearing (JIS) Abbreviations in parenthesis are according to ABMA definitions

Inner Ring Tolerance (For Bore diameters of less than or equal to 18 mm) according to JIS standards.

All values are specified in µm

PRECISION GRADE BORE VARIATION BORE RADIAL RUNOUT SIDE RUNOUT AXIAL RUNOUT WIDTH VARIATION INEQUALITY OF WIDTH Δdmp Δds Kia Sd Sia ΔBs VBs   UPPER LOWER UPPER LOWER MAX MAX MAX UPPER LOWER MAX 0        0       -8        -        -       10        -        -        0     -40*1    -120       12*1       15*2       20 6        0       -7        -        -       5*1       6*2       7        -        -        0     -40*1    -120       12*1       15*2       20 5        0       -5        -        -       4        7        7        0     -40*2     -80         5 4        0       -4        0       -4       2.5        3        3        0     -40*2     -80        2.5 2        0       -2.5        0       -2.5       1.5        1.5         1.5        0     -40*2     -80        1.5

*1: For Bore Diameters of less than or equal to 2.5 mm. *2: For Bore Diameters of less than or equal to 10 mm.

Outer Ring Tolerance (For Outer Rings of less than or equal to 30 mm) according to JIS standards.

All values are specified in µm

PRECISION GRADE OUTSIDE DIAMETER VARIATION OD RADIAL RUNOUT SIDE RUNOUT AXIAL RUNOUT WIDTH VARIATION INRQUALITY OF WIDTH ΔDmp ΔDs Kea SD Sea ΔCs Vcs   UPPER LOWER UPPER LOWER MAX MAX MAX UPPER LOWER MAX 0        0       -8*1       -9        -        -       15        -        -        0     -40*2    -120       12*2       15*3       20 6        0       -7*1      -8        -        -        8*1        9        -        -        0     -40*2    -120       12*2       15*3       20 5        0      -5*1      -6       -       -        5*1        6        8        8        0     -40*3     -80        5 4        0      -4*1      -5       0     -4*1     -5        3*1        4        4        5        0     -40*3     -80        2.5 2       0      -2.5*1      -4       0     -2.5*1     -4        1.5*1        2.5       1.5       1.5*1       2.5        0     -40*3     -80        1.5

*1: For Outside Diameters of less than or equal to 18 mm. *2: For Bore Diameters of less than or equal to 2.5 mm. *3: For Bore Diameters of less than or equal to 10 mm.

Flange Diameter Tolerance (According to JIS).

All values are specified in µm

D (mm) Column 1 Column 2 ΔD1s More than Less than or equal to UPPER LOWER UPPER LOWER   10           +220             -36              0           -36 10 18           +270             -43              0           -43 18 30           +330             -52              0           -52

Notes : Apply "Column 2" in above table when the flange outer diameter surface is taken the positioning.

Flange Width Tolerance, Limiting Value and Tolerance of rotation Accuracy Related with Flange (JIS).

All values are specified in µm

D (mm) Grade 0, 6 Grade 5, 4, 2 Grade 0, 6 Grade 5 Grade 4 Grade 2 ΔCIs VCIs More than Less than or equal to UPPER LOWER UPPER LOWER MAX      2.5*1      30        0        0      -40*2     -120        0        0      -40*3      -80      12*2      15*3      20        5       2.5       1.5 　D (mm) Grade 5 Grade 4 Grade 2 Grade 5 Grade 4 Grade 2 SD1 Sea1 More than Less than or equal to MAX MAX           2.5*1           18          18          30          8          8          4         4         1.5         1.5          11          11           7           7          3          4

*1: 2.5 mm is included to the dimension's division. *2: For Bore Diameters of less than or equal to 2.5 mm. *3: For Bore Diameters of less than or equal to 10 mm.

Inner Ring Tolerance (For Bore diameters of less than or equal to 18 mm) according to ABMA standards.

All values are specified in µm

PRECISION GRADE BORE VARIATION BORE RADIAL RUNOUT BORE RUNOUT WIDTH SIDE AXIAL RUNOUT INNER WIDTH VARIATION INEQUALITY OF WIDTH Δdmp Δds Ki Sdi Si ΔBs VBs ABEC UPPER LOWER UPPER LOWER MAX MAX MAX UPPER LOWER MAX 3P        0      -5.1     +2.5      -7.6      5.1*1      7.6        -        -       0     -127         - 5P        0      -5.1       0      -5.1      3.8      7.6      7.6       0      -25.4       5.1 7P        0      -5.1       0      -5.1      2.5      2.5      2.5       0      -25.4       2.5 9P        0      -2.5       0      -2.5      1.3      1.3      1.3       0      -25.4       1.3

*1: For Bore Diameters of less than or equal to 10 mm.

Outer Ring Tolerance (For Outer Rings of less than or equal to 30 mm) according to ABMA standards.

All values are specified in µm

PRECISION GRADE OD VARIATION OD RADIAL RUNOUT OD RUNOUT WIDTH SIDE AXIAL RUNOUT OUTER WIDTH VARIATION INEQUALITY OF WIDTH ΔDmp ΔDs Ke SD Se ΔCs Vcs OPEN BEARING SHIELDED BRG ABEC UPPER LOWER UPPER LOWER UPPER LOWER MAX MAX MAX UPPER LOWER MAX 3P       0     -7.6     +2.5   -10.2     +5.1   -12.7   10.2       -       -       0   -127        - 5P       0     -5.1       0     -5.1     +1     -6.1     5.1     7.6     7.6         0    -25.4       5.1 7P       0     -5.1       0     -5.1     +1     -6.1     3.8     3.8     5.1         0    -25.4       5.1 9P       0     -2.5*1     -3.8       0     -2.5*1     -3.8       -       -     1.3*1     2.5     1.3     1.3*1     2.5         0    -25.4       1.3

*1: For Outside Diameters of less than or equal to 18 mm.

Radial Ball Bearing chamfer dimension of inner ring upper and lower Limits.

All values are specified in mm

rsmin d-Nominal Bore Diameter (mm) rsmax More than Less than or equal to Radial Direction  Axial Direction 0.05                    -                    -                   0.1                  0.2 0.08                    -                    -                   0.16                  0.3 0.1                    -                    -                   0.2                  0.4 0.15                    -                    -                   0.3                  0.6 0.2                    -                    -                   0.5                  0.8 0.3                    -                  40                   0.6                  1                  40                    -                   0.8                  1 0.6                    -                  40                   1                  2                  40                    -                   1.3                  2 1                    -                  50                   1.5                  3                  50                    -                   1.9                  3