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Home ... Engineering Information... Miniature & Small ball bearings... Selecting a Bearing... 7. Tolerance and precision grade

Miniature & Small ball bearings -7. Tolerance and precision grade

The bearings are classified into certain precision grades. The tolerances for each grade are found in JIS and ANSI/ABMA. Minebea's products are based on JIS B 1514-1,-3, ANSI/ABMA Std.12.2 and ANSI/ABMA Std.20 The symbols used in the specification are as follows.


Symbol

  • ■Dimensions
  • d :Nominal Bore Diame
  • D :Nominal Outside Diameter
  • D1 :Outer ring flange outside diameter, basic
  • B :Nominal Inner Ring Width
  • C :Nominal Outer Ring Width
  • r  :Chamfer Dimension of Inner Ring or Outer Ring
  •  
  • ■Dimensional Differences
  • Δds :Dimensional difference of bore diameter
  • Δdmp:Dimensional difference of mean bore diameter in the plane
  • dm):Dimensional difference of mean bore diameter
  • ΔDs :Dimensional difference of outside diameter
  • ΔDmp:Dimensional difference of mean outside diameter in the plane
  • Dm):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
  •  
  • ■Limit Values of Chamfer/Radius Dimension
  • rs  :Chamfer dimension of inner ring or outer ring
  • rs min:Minimum dimension limit of inner ring and outer ring chamfer
  • rs max:Maximum dimension limit of inner ring and outer ring chamfer
  • ■Inequality of Dimensions
  • VBs :Inequality of inner ring width
  • VCs :Inequality of outer ring width
  • VC1s:Inequality of flanged width
  •  
  • ■Rotation Precision
  • Kia(Ki) :Radial runout of inner ring
  • Sia(Si) :Axial runout of inner ring
  • Sd(Sdi):Side runout of inner ring [runout of inner ring reference face with respect to the bore]
  • Kea(Ke):Radial runout of outer ring
  • Sea(Se):Axial runout of outer ring
  • SD(SD):Side runout of outer ring [variation of outside surface generatrix inclination with respect to the outer ring reference face]
  • SD1   :[variation of outside surface generatrix inclination with respect to the outer ring flange back face]
  • Seal   :Axial runout of outer ring flange back face
  •  
  • Remark ( ) is defined by ANSI/ABMA.
  • Reference [ ] is the expression used in previous JIS.
  • Attention : Above is only for radial ball bearing.

Referred from JIS B 1514-1

Tolerance of inner ring d ≦ 18mm

Unit : μm

Grade Dimensional difference Radial Runout Perpendicularity Axial runout Dimensional difference of width Inequality of width
Δdmp Δds Kia Sd Sia ΔBs VBs
Upper Bottom Upper Bottom MAX MAX MAX Upper Bottom MAX
Grade 0 0 -8 - - 10 - - 0 - 40*1
-120
12*1
15*2
20
Grade 6 0 -7 - - 5*1
6*2
7
- - 0 - 40*1
-120
12*1
15*2
20
Grade 5 0 -5 - - 4 7 7 0 - 40*2
- 80
5
Grade 4 0 -4 0 -4 2.5 3 3 0 - 40*2
- 80
2.5
Grade 2 0 -2.5 0 -2.5 1.5 1.5 1.5 0 - 40*2
- 80
1.5

*1 the values apply only up to and including d = 2.5mm.
*2 the values apply only up to and including d = 10mm.

Tolerances of outer ring D ≦ 30mm

Unit : μm

Grade Dimensional difference Radial runout Perpendicularity Axial runout Dimensional difference of width Inequality of width
ΔDmp ΔDS Kea SD Sea ΔCs VCs
Upper Bottom Upper Bottom MAX MAX MAX Upper Bottom MAX
Grade 0 0 -8*1
-9
- - 15 - - 0 - 40*2
-120
12*2
15*3
20
Grade 6 0 -7*1
-8
- - 8*1
9
- - 0 - 40*2
-120
12*2
15*3
20
Grade 5 0 -5*1
-6
- - 5*1
6
8 8 0 - 40*3
- 80*4
5
Grade 4 0 -4*1
-5
0 -4*1
-5
3*1
4
4 4 0 - 40*3
- 80*4
2.5
Grade 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*4
1.5

*1 the values apply only up to and including D = 18mm.
*2 the values apply only up to and including d = 2.5mm.
*3 the values apply only up to and including d = 10mm.
*4 the values apply only up to and including d = 18mm.

Flange outside diameter tolerance

Unit : μm

D1 Column 1 Column 2
(mm) ΔD1s
Over Incl. Upper Bottom Upper Bottom
10 +220 -36 0 -36
10 18 +270 -43 0 -43
18 30 +330 -52 0 -52

Remarks : When the flange outside diameter is used for location, column 2 shall apply.

Tolerances of flange width and tolerance of rotation precision related to flange

Unit : μm

D Grade 0, Grade 6 Grade 5, Grade 4, Grade 2 Grade 0, Grade 6 Grade 5 Grade 4 Grade 2
(mm) ΔC1s VC1s
Over Incl. Upper Bottom Upper Bottom MAX
2.5*1 30 0
-40*2
-120
0 -40*3
-80
12*2
15*3
20
5 2.5 1.5

Unit : μm

D Grade 5 Grade 4 Grade 2 Grade 5 Grade 4 Grade 2
(mm) SD1 Sea1
Over Incl. MAX MAX
2.5*1
18
18
30
8
8
4
4
1.5
1.5
11
11
7
7
3
4

*1 D = 2.5mm is included in this dimension division.
*2 the values apply only up to and including d = 2.5mm.
*3 the values apply only up to and including d = 10mm.

Referenced from ANSI/ABMA Std.12.2

Inner Ring tolerance d ≦ 18mm

Unit : μm

Grade
ABEC
Δdmp* Δds Ki Sdi Si ΔBs VBs
Upper Bottom Upper Bottom MAX MAX MAX Upper Bottom 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

* Basically, grade 3P is provided as Δdm.
*1 the values apply only up to and including d = 10mm.

Outer Ring tolerance D ≦ 30mm

Unit : μm

Grade
ABEC
ΔDmp* ΔDs Ke Cs Se ΔCs VCs
Open shield/seal
Upper Bottom Upper Bottom Upper Bottom MAX MAX MAX Upper Bottom 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 2.5
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

* Basically, grade 3P is provided as ΔDm.
*1 the values apply only up to and including D = 18mm.

Referred from ANSI/ABMA Std.20

Inner Ring tolerance d ≦ 18mm

Unit : μm

Grade
ABEC
Δdmp Kia Sia ΔBs VBs
Upper Bottom MAX MAX Upper Bottom MAX
1 0 -8 10 15*1
20
0
0
- 40*1
-120
12*1
15*2
20

*1 the values apply only over and including d = 0.6mm or up to and including d = 10mm.
*2 the values apply only up to and including d = 10mm.

Outer Ring tolerance D ≦ 30mm

Unit : μm

Grade
ABEC
ΔDmp Kea Sea ΔCs VCs
Upper Bottom MAX MAX Upper Bottom MAX
1 0 -8*1
-9
15 15*2
20*1
25
0 - 40*3
-120
12*3
15*4
20

*1 the values apply only up to and including D = 18mm.
*2 the values apply only up to and including D = 6mm.
*3 the values apply only up to and including d = 2.5mm.
*4 the values apply only up to and including d = 10mm.

Referenced from JIS B 1514-3

Maximum values of chamfer dimension for radial bearings

Unit : μm

rs min d rs max
Over Incl. Radial direction Axial direction
0.05
0.08
0.1
0.15
0.2
-
-
-
-
-
-
-
-
-
-
0.1
0.16
0.2
0.3
0.5
0.2
0.3
0.4
0.6
0.8
0.3 -
40
40
-
0.6
0.8
1
1
0.6 -
40
40
-
1
1.3
2
2
1 -
50
50
-
1.5
1.9
3
3

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