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ACCURACY OF BALL BEARING UNITS

1. Radial Internal Clearance of Bearings

The radial internal clearance of the bearing for the unit is same with the reference value of JIS B 1520 deep-groove ball bearings. Generally, the normal clearance is adopted for cylindrical bore bearings and C3 clearance which is a little greater is adopted for tapered bore bearings. When the environmental temperature is very high or when the temperature difference between the outer and inner rings is large, a larger clearance must be adopted because the clearance decreases due to thermal expansion of the bearings materials and temperature gradient in the bearing.
1.1 Cylindrical bore bearings                                                       Unit=0.001mm

Bore diameter
d (mm)

C2

N

C3

C4

over

incl.

min.

max.

min.

max.

min.

max.

min.

max.

10

18

3

18

11

25

18

33

25

45

18

24

5

20

13

28

20

36

28

48

24

30

5

20

13

28

23

41

30

53

30

40

6

20

15

33

28

46

40

64

40

50

6

23

18

36

30

51

45

73

50

65

8

28

23

43

38

61

55

90

65

80

10

30

25

51

46

71

65

105

80

100

12

36

30

58

53

84

75

120

100

120

15

41

36

66

61

97

90

140

120

140

18

48

41

81

71

114

105

160

1.2 Tapered bore bearings                         Unit=0.001mm

Bore diameter
d (mm)

C2

N

C3

over

incl.

min.

max.

min.

max.

min.

max.

10

18

10

25

18

33

25

45

18

24

12

28

20

36

28

48

24

30

12

28

23

41

30

53

30

40

13

33

28

46

40

64

40

50

14

36

30

51

45

73

50

65

18

43

38

61

55

90

65

80

20

51

46

71

65

105

80

100

24

58

53

84

75

120

100

120

28

66

61

97

90

140

120

140

33

81

71

114

105

160

2.  Dimensional Accuracies of Bearings
The dimensional accuracy of RiccoTek Bearings follows the dimensional accuracy prescribed in ISO/TC4/SC6 ball bearings for rolling bearing units.
    2.1 Accuracies of outer ring                                                              Unit=0.001mm

D(mm)

Dmp

Kea

over

incl.

max.

min.

max.

30

50

0

-11

20

50

80

0

-13

25

80

120

0

-15

35

120

150

0

-18

40

150

180

0

-25

45

180

250

0

-30

50

250

315

0

-35

60

D---------------outside diameter of bearing.

  Dmp-------deviation of mean outside diameter  Kea-------------radial run out of outer ring.

  2.2 Accuracies of inner ring

d(mm)

Cylindrical bore bearing

Kia

Bore diameter

Bs,Cs

UC,HC,SA,SB,SER

SC

Bs,Cs

dmp

Vdp

dmp

Vdp

over

Incl.

Max.

Min.

Max.

Max.

Min.

Max.

Min.

Min.

Max.

10

18

+15

0

10

0

-8

6

0

-120

15

18

30

+18

0

12

0

-10

8

0

-120

18

30

50

+21

0

14

0

-12

9

0

-120

20

50

80

+24

0

16

0

-15

11

0

-150

25

80

120

+28

0

19

-

-

-

0

-200

30

120

180

+33

0

22

-

-

-

0

-250

35

d----------------bore diameter
dmp--------deviation of mean bearing bore diameter in a single plane.
Vdp-------------variation of bearing bore diameter in a single radial plane.
Bs------------deviation of a single inner ring width.
Cs-------------deviation of a single outer ring width.
Kia-----------------radial run out of inner ring.
 
2.3 Accuracies of tapered bore 

mm

dmp

d1mp-dmp

Vdp1)

over

incl

max.

min.

max.

min.

max.

18

30

+33

0

+21

0

13

30

50

+39

0

+25

0

15

50

80

+46

0

+30

0

19

80

120

+54

0

+35

0

25

120

180

+63

0

+40

0

31

1).Applies in any single radial plane of the bore.
d--------bore diameter
d1-------diameter at the theoretical large end of a basically tapered bore d1-d+1/12B
dmp----deviation of mean bore diameter in a single plane(for a basically bore, dmp refers to the theoretical small end of the bore).
d1mp-----deviation of mean bore diameter in a single plane at the theoretical large end of a basically tapered bore.
Vdp-----variation on bore diameter in a single radial plane.
B--------inner ring width 

Tolerance in distance n from center line of spherical outer ring to side of inner ring      
Unit=0.001mm

 

Dimensions of bore diameter d(mm)

Tolerance of n

Over

Incl.

 

-

50

+/-200

50

80

+/-250

80

120

+/-300

120

-

+/-350

Tolerance of spherical bore diameter of housings                                    Unit=0.001mm

 

Dimension of spherical bore diameter D.(mm)

Housing for loose fit

Housing for sliding fit

Housing for sliding fit

Symbol H

Symbol J

Symbol K

D1m

D1

D1m

D1

D1m

D1

Over

Incl.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Min.

30

50

+25

0

+30

-5

+14

-11

+19

-16

+7

-18

+12

-23

50

80

+30

0

+36

-6

+18

-12

+24

-18

+9

-21

+15

-27

80

120

+35

0

+42

-7

+22

-13

+29

-20

+10

-25

+17

-32

120

180

+40

0

+48

-8

+26

-14

+34

-22

+12

-28

+20

-36

180

250

+46

0

+55

-9

+30

-16

+39

-25

+13

-33

+22

-42

250

315

+52

0

+62

-10

+36

-16

+46

-26

+16

-36

+26

-46

Notes:
a).D1m is given by the following equation, where D1max and D1min in the equation are maximum and minimum values measured respectively.  D1m= D1max+ D1 min  /2
b). Dimensional tolerance for spherical inside of housings are divided into loose fit H, sliding fit J and sliding fit K.
c). When the contained bearing are equipped with locking-pins, loose fit is applied.
 
Tolerance of castings. 
Dimensional accuracies of casting follow JIS B 0407 [Permissible deviations in dimensions without tolerance indication for iron castings] medium class accuracy.          Unit=mm

 

Tolerance in length

Tolerance in thickness

Dimensions

Tolerance

Dimensions

Tolerance

over

Incl.

over

Incl.

-

120

±1.5

-

-

-

120

250

±2.0

-

10

±1.5

250

400

±3.0

10

18

±2.0

400

800

±4.0

18

30

±3.0

800

1600

±6.0

30

50

±3.5

 

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