Bearings boundary dimensions and tolerances

The dimensional and running accuracy of rolling bearings has been standardized internationally. In addition to the Normal tolerances, the ISO standards also cover closer tolerances, such as tolerance class 6, 6X

The tolerance symbols and their definitions are provided in the table below.

Radial bearings inner and outer ring                             

d

Bore diameter

D

Outside diameter

B

Inner ring width

C

Outer ring width

 

Δdmp

1. Cylindrical bore: Deviation of mean bore diameter in a single plane

2. Tapered bore: Deviation of mean bore diameter at the theoretical small end from its nominal size

 

Vdsp

Variation of bore diameter in a single plane

Vdmp

Variation of mean bore diameter

ΔBs

Deviation of a single inner ring width

VBs

Variation of inner ring width

Kia; Kea

Radial runout of inner ring of assembled bearing ; radial runout of outer ring of assembled bearing

ΔDmp

Deviation of mean outside diameter in a single plane

VDsp

Variation of outside diameter in a single plane

 

VDmp

Variation of mean outside diameter

ΔCs

Deviation of single outer ring width

VCs

Variation of outer ring width

Tapered roller bearings                                                    

 

ΔTs

Deviation of the actual (assembled) bearing width

 

ΔT1s

Deviation of the actual effective width of inner subunit

 

ΔT2s

Deviation of the actual effective width of outer ring

 

Thrust bearings                                                                                            

 

d

Nominal bore diameter  of shaft washer, single direction bearing

 

Δdmp

Deviation of the shaft washer mean bore  diameter in a single plane, single direction bearing

 

Vdsp

Variation of the shaft washer single bore diameter in a single plane, single direction bearing

 

Si

Thickness variation of the shaft washer for thrust bearings, raceway to back face

 

D

Nominal outside diameter of housing washer

 

ΔDmp

Deviation of the housing washer mean outside diameter in a single plane

 

VDsp

Variation of the housing washer single outside diameter in a single plane

 

 

 

Se

Thickness variation of the housing washer for thrust bearings raceway to back face

 

ΔTs

Deviation of assembled bearing height from its nominal size, single direction be­aring

 

ΔT1s

Deviation of assembled bearing height from its nominal size, single direction bearing with a seat washer

 

       

 

TOLERANCE class

Radial bearings                                                                                      

(except tapered roller bearings)                                                          

Normal tolerance class                                                                   

Inner ring       Tolerances, µm   

d,mm

Δdmp

Vdsp

Vdmp

Kia

                ΔBs

 

VBs

 

diameter series

 

7,8,9

0,1

2,3,4

all

 

normal

 

> 

high

low

max.

max.

max.

high

low

max.

-

2,5

0

-8

10

8

6

6

10

0

-40

12

2,5

10

0

-8

10

8

6

6

10

0

-120

15

10

18

0

-8

10

8

6

6

10

0

-120

20

18

30

0

-10

13

10

8

8

13

0

-120

20

30

50

0

-12

15

12

9

9

15

0

-120

20

50

80

0

-15

19

19

11

11

20

0

-150

25

80

120

0

-20

25

25

15

15

25

0

-200

25

120

180

0

-25

31

31

19

19

30

0

-250

30

180

250

0

-30

38

38

23

23

40

0

-300

30

250

315

0

-35

44

44

26

26

50

0

-350

35

315

400

0

-40

50

50

30

30

60

0

-400

40

400

500

0

-45

56

56

34

34

65

0

-450

50

500

630

0

-50

63

63

38

38

70

0

-500

60

 

Outer ring      Tolerances, µm          

D, mm

ΔDmp

VDsp1)

VDmp1)

Kea

 

ΔCs

 

 

VCs

 

open bearing

 

capped  bearing2)

diameter series 

7,8,9

0,1

2,3,4

2,3,4

> 

high

 

low

 

max.

 

max.

 

max.

 

high

 

low

 

max.

 

2,5

18

0

-8

10

8

6

10

6

15

ΔСs and VСs

are identical

to ΔBs and VBs

of the same bearing

 

 

18

30

0

-9

12

9

7

12

7

15

30

50

0

-11

14

11

8

16

8

20

50

80

0

-13

16

13

10

20

10

25

80

120

0

-15

19

19

11

26

11

35

120

150

0

-18

23

23

14

30

14

40

150

180

0

-25

31

31

19

38

19

45

180

250

0

-30

38

38

23

-

23

50

250

315

0

-35

44

44

26

-

26

60

315

400

0

-40

50

50

30

-

30

70

400

500

0

-45

56

56

34

-

34

80

500

630

0

-50

63

63

38

-

38

100

                         

1)  Applied to bearings prior to mounting and after removal of internal or external snap ring

2)  Capped bearings - sealed or shielded bearings

 

Tolerance class 6                                                                                                        

Inner ring    Tolerances, µm        

d,mm

Δdmp

Vdsp

Vdmp

 

Kia

 

                                                                            ΔBs

VBs

 

 

diameter series 

 

7,8,9

0,1

2,3,4

all

normal

> 

high

low

max.

max.

max.

high

low

max.

-

2,5

0

-7

9

7

5

5

5

0

-40

12

2,5

10

0

-7

9

7

5

5

6

0

-120

15

10

18

0

-7

9

7

5

5

7

0

-120

20

18

30

0

-8

10

8

6

6

8

0

-120

20

30

50

0

-10

13

10

8

8

10

0

-120

20

50

80

0

-12

15

15

9

9

10

0

-150

25

80

120

0

-15

19

19

11

11

13

0

-200

25

120

180

0

-18

23

23

14

14

18

0

-250

30

180

250

0

-22

28

28

17

17

20

0

-300

 

30

250

315

0

-25

31

31

19

19

25

0

-350

35

315

400

0

-30

38

38

23

23

30

0

-400

40

400

500

0

-35

44

44

26

26

35

0

-450

45

500

630

0

-40

50

50

30

30

40

0

-500

50

 

Outer ring     Tolerances, µm    

D, mm

ΔDmp

VDsp1)

VDmp1)

Kea

 

ΔCs

 

 

 

VCs

 

 

open bearing

 

capped bearing2)

diameter series

 

7,8,9

0,1

2,3,4

0,1,2,3,4

> 

high

low

max.

max.

max.

high

low

max.

2,5

18

0

-7

9

7

5

9

5

8

ΔСs and VСs

are identical

to ΔBs and VBs

of the same bearing

 

 

 

18

30

0

-8

10

8

6

10

6

9

30

50

0

-9

11

9

7

13

7

10

50

80

0

-11

14

11

9

16

8

13

80

120

0

-13

16

16

10

20

10

18

120

150

0

-15

19

19

11

25

11

20

150

180

0

-18

23

23

14

30

14

23

180

250

0

-20

25

25

15

-

15

25

250

315

0

-25

31

31

19

-

19

30

315

400

0

-28

35

35

21

-

21

35

400

500

0

-33

41

41

25

-

25

40

500

630

0

-38

48

48

29

-

29

50

630

800

0

-45

56

56

34

-

34

60

                         

 

1)  Applied to bearings prior to mounting and after removal of internal or external snap ring

2)  Capped bearings - sealed or shielded bearings

 

Tapered roller bearings                                        

Normal tolerance class                                                                   

Inner ring      Tolerances, µm  

d, mm

Δdmp

Vdsp

Vdmp

ΔBs

Kia

ΔTs

ΔT1s

ΔT2s

> 

high

low

high

low

high

low

high

low

high

low

10

18

0

-12

12

9

0

-120

15

+200

0

+100

0

+100

0

18

30

0

-12

12

9

0

-120

18

+200

0

+100

0

+100

0

30

50

0

-12

12

9

0

-120

20

+200

0

+100

0

+100

0

50

80

0

-15

15

11

0

-150

25

+200

0

+100

0

+100

0

80

120

0

-20

20

15

0

-200

30

+200

-200

+100

-100

+100

-100

120

180

0

-25

25

19

0

-250

35

+350

-250

+150

-150

+200

-100

180

250

0

-30

30

23

0

-300

50

+350

-250

+150

-150

+200

-100

250

315

0

-35

35

26

0

-350

60

+350

-250

+150

-150

+200

-100

315

400

0

-40

40

30

0

-400

70

+400

-400

+200

-200

+200

-200

 

Outer ring    Tolerances, µm  

D, mm

ΔDmp

VDsp

VDmp

ΔCs

Kea

> 

high

low

high

low

18

30

0

-12

12

9

0

-120

18

30

50

0

-14

14

11

0

-120

20

50

80

0

-16

16

12

0

-150

25

80

120

0

-18

18

14

0

-200

35

120

150

0

-20

20

15

0

-250

40

150

180

0

-25

25

19

0

-250

45

180

250

0

-30

30

23

0

-300

50

250

315

0

-35

35

26

0

-350

60

315

400

0

-40

40

30

0

-400

70

400

500

0

-45

45

34

0

-450

80

500

630

0

-50

60

38

0

-500

100

630

800

0

-75

80

55

0

-750

120

 

Tolerance class 6X                                                                                              

Inner ring    Tolerances, µm   

d, mm

Δdmp

Vdsp

Vdmp

ΔBs

Kia

ΔTs

ΔT1s

ΔT2s

> 

high

low

high

low

high

low

high

low

high

low

10

18

0

-12

12

9

0

-50

15

+100

0

+50

0

+50

0

18

30

0

-12

12

9

0

-50

18

+100

0

+50

0

+50

0

30

50

0

-12

12

9

0

-50

20

+100

0

+50

0

+50

0

50

80

0

-15

15

11

0

-50

25

+100

0

+50

0

+50

0

80

120

0

-20

20

15

0

-50

30

+100

-200

+50

0

+50

0

120

180

0

-25

25

19

0

-50

35

+150

-250

+50

0

+100

0

180

250

0

-30

30

23

0

-50

50

+150

-250

+50

0

+100

0

250

315

0

-35

35

26

0

-50

60

+200

-250

+100

0

+100

0

315

400

0

-40

40

30

0

-50

70

+200

-400

+100

0

+100

0

 

Outer ring    Tolerances, µm  

D, mm

ΔDmp

VDsp

VDmp

ΔCs

Kea

> 

high

low

high

low

18

30

0

-12

12

9

0

-100

18

30

50

0

-14

14

11

0

-100

20

50

80

0

-16

16

12

0

-100

25

80

120

0

-18

18

14

0

-100

35

120

150

0

-20

20

15

0

-100

40

150

180

0

-25

25

19

0

-100

45

180

250

0

-30

30

23

0

-100

50

250

315

0

-35

35

26

0

-100

60

315

400

0

-40

40

30

0

-100

70

400

500

0

-45

45

34

0

-100

80

500

630

0

-50

60

38

0

-100

100

630

800

0

-75

80

55

0

-100

120

 

 

 Thrust bearings                                                                                                

Normal tolerance class                                                                   

Tolerances, µm            

Nominal diameter, mm

Shaft washer

 

Housing washer

 

Bearing height

 

 

d

D

Δdmp

Vdsp

Si1)

ΔDmp

VDsp

Se1)

ΔTs

single direction bearing

 

ΔT1s

single direction bearing

with seat washer

 

 

> 

high

 

low

 

high

 

low

 

 

high

 

low

 

high

 

low

 

 

-

18

0

-8

6

10

0

-11

8

Identical to Si of shaft washer of the same bearing

 

-

-

-

-

 

18

30

0

-10

8

10

0

-13

10

+20

-250

+100

-250

 

30

50

0

-12

9

10

 

0

-16

12

+20

-250

+100

-250

 

50

80

0

-15

11

10

0

-19

14

+20

-300

+100

-300

 

80

120

0

-20

15

15

0

-22

17

+25

-300

+150

-300

 

120

180

0

-25

19

15

0

-25

19

+25

-400

+150

-400

 

180

250

0

-30

23

20

0

-30

23

+30

-400

+150

-400

 

250

315

0

-35

26

25

0

-35

26

+40

-400

-

-

 

315

400

0

-40

30

30

0

-40

30

+40

-500

-

-

 

400

500

0

-45

34

30

0

-45

34

+50

-500

-

-

 

500

630

0

-50

38

35

0

-50

38

+60

-600

-

-

 
                             

 

1)Applies only to thrust ball bearings with 90° contact angle

 

Tolerance class 6                                                                                                     

Tolerances, µm 

Nominal diameter, mm

Shaft washer

 

Housing washer

 

Bearing height

 

 

d

D

Δdmp

Vdsp

Si1)

ΔDmp

VDsp

Se1)

ΔTs

single direction bearing

 

ΔT1s

single direction bearing

with seat washer

 

 

> 

high

 

low

 

high

 

low

 

 

high

 

low

 

high

 

low

 

 

-

18

0

-8

6

5

0

-11

8

Identical to Si of shaft washer of the same bearing

 

 

-

-

-

-

 

18

30

0

-10

8

5

0

-13

10

+20

-250

+100

-250

 

30

50

0

-12

9

6

 

0

-16

12

+20

-250

+100

-250

 

50

80

0

-15

11

7

0

-19

14

+20

-300

+100

-300

 

80

120

0

-20

15

8

0

-22

17

+25

-300

+150

-300

 

120

180

0

-25

19

9

0

-25

19

+25

-400

+150

-400

 

180

250

0

-30

23

10

0

-30

23

+30

-400

+150

-400

 

250

315

0

-35

26

13

0

-35

26

+40

-400

-

-

 

315

400

0

-40

30

15

0

-40

30

+40

-500

-

-

 

400

500

0

-45

34

18

0

-45

34

+50

-500

-

-

 

500

630

0

-50

38

21

0

-50

38

+60

-600

-

-

 

1)Applies only to thrust ball bearings with 90° contact angle

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