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 innter 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 |
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 |
|
Bore diameter |
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 FK bearings follows the dimensional accuracy prescribed in ISO/TC4/SC6 ball bearings for rolling bearing units.
2.1Accuracies 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(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 |
△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 ruout of inner ring.
2.3Accuracies 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 |
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 devided 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 |
Rod Ends consist of an eye-shaped head with integral shank forming a housing and a standard spherical plain bearing, or a spherical plain bearing inner ring, or a spherical plain bearing ring and a sliding layer between the bore of the head and the inner ring. As a rule, rod ends are available with left or right -hand female or male threads. FKT rod ends have the sliding contact surface combinations steel-on-steel, steel-on-bronze,steel-on-PTFE composite material and steel-on-PTFE fabric.
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FK Bearing Group will be prensent to Intermach 2011 during 12--16/September/2011 in Joinville,Brazil, and we will be pleased to meet you, we are inviting you to visit our Booth number 647
Tel : +86-592-6689003/05/06/08 Export Dept.
Fax: +86-592-6689001/07
E-mail: export@fk-bearing.com