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Technical information
Bearings Dimensional Inspection |
| BEARINGS DIMENSIONAL INSPECTION |
The wrapped or thin wall bushes are not accurately mensurable in the unfitted condition. Here we list the standard measurement method.
Testing the outside diameter
The outside diameter of RCB wrapped plain bearings that have to have the interference fit (press fit) in the housing are tested with the aid of a special device. |
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In this test the outside diameter is measured under prestressing force according to DIN 1494, part 2, test A to determine the deviation Delta Z from a standard value. Test load and permissible deviation are calculated according to DIN 1494.
Normally this method is suitable for large series.
The simplified method for testing the outside diameter of plain bearings is based on DIN 1494 Method B. The test uses GO and NO GO ring gauge. The corresponding diameters of the GO and NO GO ring gauges are selected according to the DIN standard.
Normally this method is suitable for smaller series. |
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Testing the inside diameter
The inside diameter is tested according to DIN1494, part 2, test C. To perform this test, the bushes should be fixed in a ring gauge (table 5 according to DIN1494 part 1) in this condition the inside diameter can be tested with GO or NO GO plug gauges.
Normally this method is suitable for smaller series. The big size bushes recommend use of a three-point micrometer is preferable. |
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Testing the thrust washer
Beside the thickness, the flatness of a washer is of particular importance as it has impact on the life of both the washer and its mate.
We use very helpful test in which the washer falls through the gap between two plain parallel plates of a gauge under its dead weight. The plates must be big enough to cover the whole washer. |
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| Design of Bearing Arrangements |
| DESIGN OF BEARING ARRANGEMENTS |
Housing
Bushes
The housing bore should have a chamfer fGx20¡ã¡À5¡ã,This chamfer makes it easier to press the bushes into the housing.
Housing bore
diameter dG |
Chamfer with fG |
dG¡Ü30 |
0.8¡À0.3 |
30<dG¡Ü80 |
1.2¡À0.4 |
80<dG¡Ü180 |
1.8¡À0.8 |
180<dG |
2.5¡À1.0 |
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Flange Bushes
The radius at the transition from the radial to the axial component must be taken into consideration for flange bushes. A sufficiently large chamfer must be provided on the housing to prevent the flanged bushes fouling in the area of the radius. Sufficient support must be provided for the flange in applications with axial loading.
Housing bore
diameter dG |
Chamfer with fG |
dG¡Ü10 |
1.2¡À0.2 |
10<dG |
1.7¡À0.2 |
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Shaft
o make fitting easier, the shaft ends should be chamfered. All sharp edges which could damage the sliding layer must be broken. Higher surface qualities will extend the service life only slightly whereas greater roughness depths will reduce the service life considerably. Ground or drawn surfaces are preferred. The surface finish of the mating material should be between Ra 0.2- Ra0.8 um obtained by grinding normally. |
incorrect
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correct
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Seals
If increased levels of contamination occur or the bearing is used in an aggressive environment, the bearing position should be protected. The usual solution is to design the surrounding structure so that the contamination cannot reach the bearing position. A collar of grease may also be used or shaft seals if the level of contamination is particularly high. |
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| Mating Tolerance |
SHAFT TOLERANCE TABLE (ISO) |
¡Ý |
£¼ |
c9 |
d8 |
e7 |
e8 |
F7 |
g6 |
h5 |
h6 |
h7 |
h8 |
js6 |
js7 |
k6 |
m6 |
n6 |
p6 |
p7 |
r6 |
s6 |
¡ª |
3 |
-60
-85 |
-20
-34 |
-14
-24 |
-14
-28 |
-6
- 16 |
-2
-8 |
0
-4 |
0
-6 |
0
-10 |
0
-14 |
¡À3 |
¡À5 |
+6
0 |
+8
+2 |
+10
+4 |
+12
+6 |
+16
+6 |
+16
+10 |
+20
+14 |
3 |
6 |
-70
-100 |
-30
-48 |
-20
-32 |
-20
-38 |
-10
-22 |
-4
-12 |
0
-5 |
0
-8 |
0
-12 |
0
-18 |
¡À4 |
¡À6 |
+9
+1 |
+12
+4 |
+16
+8 |
+20
+12 |
+24
+12 |
+23
+15 |
+27
+19 |
6 |
10 |
-80
-116 |
-40
-62 |
-25
-40 |
-25
-47 |
-13
-28 |
-5
-14 |
0
-6 |
0
-9 |
0
-15 |
0
-22 |
¡À4.5 |
¡À7 |
+10
+1 |
+15
+6 |
+19
+10 |
+24
+15 |
+30
+15 |
+28
+19 |
+32
+23 |
10 |
18 |
-95
-138 |
-50
-77 |
-32
-50 |
-32
-59 |
-16
-34 |
-6
-17 |
0
-8 |
0
-11 |
0
-18 |
0
-27 |
¡À5.5 |
¡À9 |
+12
+1 |
+18
+7 |
+23
+12 |
+29
+18 |
+36
+18 |
+34
+23 |
+39
+28 |
18 |
24 |
-110
-162 |
-65
-98 |
-40
-61 |
-40
-73 |
-20
-41 |
-7
-20 |
0
-9 |
0
-13 |
0
-21 |
0
-33 |
¡À6.5 |
¡À10 |
+15
+2 |
+21
+8 |
+28
+15 |
+35
+22 |
+43
+22 |
+41
+28 |
+48
+35 |
24 |
30 |
30 |
40 |
-120
-182 |
-80
-119 |
-50
-75 |
-50
-89 |
-25
-50 |
-9
-25 |
0
-11 |
0
-16 |
0
-25 |
0
-39 |
¡À8 |
¡À12 |
+18
+2 |
+25
+9 |
+33
+17 |
+42
+26 |
+51
+26 |
+50
+34 |
+59
+43 |
40 |
50 |
-130
-192 |
50 |
65 |
-140
-214 |
-100
-146 |
-60
-90 |
-60
-106 |
-30
-60 |
-10
-29 |
0
-13 |
0
-19 |
0
-30 |
0
-46 |
¡À9.5 |
¡À15 |
+21
+2 |
+31
+11 |
+39
+20 |
+51
+32 |
+62
+32 |
+60
+41 |
+72
+53 |
65 |
80 |
-150
-224 |
+62
+43 |
+78
+59 |
80 |
100 |
-170
-257 |
-120
-174 |
-72
-107 |
-72
-126 |
-36
-71 |
-12
-34 |
0
-15 |
0
-22 |
0
-35 |
0
-54 |
¡À11 |
¡À17 |
+25
+3 |
+35
+13 |
+45
+23 |
+59
+37 |
+72
+37 |
+73
+51 |
+93
+71 |
100 |
120 |
-180
-267 |
+76
+54 |
+101
+79 |
120 |
140 |
-200
-300 |
-145
-208 |
-85
-125 |
-85
-148 |
-43
-83 |
-14
-39 |
0
-18 |
0
-25 |
0
-40 |
0
-63 |
¡À12.5 |
¡À20 |
+28
+3 |
+40
+15 |
+52
+27 |
+68
+43 |
+83
+43 |
+88
+63 |
+117
+92 |
140 |
160 |
-210
-310 |
+90
+65 |
+125
+100 |
160 |
180 |
-230
-330 |
+93
+68 |
+133
+108 |
180 |
200 |
-240
-355 |
-170
-242 |
-100
-146 |
-100
-172 |
-50
-96 |
-15
-44 |
0
-20 |
0
-29 |
0
-46 |
0
-72 |
¡À14.5 |
¡À23 |
+33
+14 |
+46
+17 |
+60
+31 |
+79
+50 |
+96
+50 |
+106
+77 |
+151
+122 |
200 |
225 |
-260
-375 |
+109
+80 |
+159
+130 |
225 |
250 |
-280
-395 |
+113
+84 |
+169
+140 |
250 |
280 |
-300
-430 |
-190
-271 |
-110
-162 |
-110
-191 |
-56
-108 |
-17
-49 |
0
-23 |
0
-32 |
0
-52 |
0
-81 |
¡À16 |
¡À26 |
+36
+4 |
+52
+20 |
+66
+34 |
+88
+56 |
+108
+56 |
+126
+94 |
+190
+158 |
280 |
315 |
-330
-460 |
+130
+98 |
+202
+170 |
315 |
355 |
-360
-500 |
-210
-299 |
-125
-182 |
-125
-214 |
-62
-119 |
-18
-54 |
0
-25 |
0
-36 |
0
-57 |
0
-89 |
¡À18 |
¡À28 |
+40
+4 |
+57
+21 |
+73
+37 |
+98
+62 |
+119
+62 |
+114
+108 |
+226
+190 |
355 |
400 |
-400
540 |
+105
+114 |
+224
+208 |
400 |
450 |
-440
-540 |
-230
-327 |
-135
-198 |
-135
-232 |
-68
-131 |
-20
-60 |
0
-27 |
0
-40 |
0
-63 |
0
-97 |
¡À20 |
¡À31 |
+45
+5 |
+63
+23 |
+80
+40 |
+108
+68 |
+131
+68 |
+166
+126 |
+272
+232 |
450 |
500 |
-480
-635 |
+172
+132 |
+292
+252 |
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