Ball Bearing Housed Unit Page A-6 Ball Bearing Housed Units-Engineering

A-6 TIMKEN BALL BEARING HOUSED UNIT CATALOG Download 3D Models and 2D Drawings at cad.timken.com BALL BEARING HOUSED UNITS INTERNAL CLEARANCE RADIAL INTERNAL CLEARANCE The radial internal clearance of radial contact ball bearings can be defined as the average outer ring raceway diameter minus the average inner ring raceway diameter minus twice the ball diameter. RADIAL BALL BEARINGS While manufacturing ball bearings, it is standard practice to assemble rings and balls with a specified internal clearance (table A-2). This characteristic is necessary to absorb the effect of press fitting the bearing rings at mounting. Internal clearance is sometimes utilized to compensate for thermal expansion of bearings, shafts and housings, or to provide a contact angle in the bearing after mounting. Internal clearance can be measured by gaging either radially or axially. Radial measurement is accepted as the more significant characteristic because it is more directly related to shaft and housing fits. It also is the method prescribed by the American Bearing Manufacturers Association (ABMA). Radial internal clearance can be measured mechanically by moving the outer ring horizontally, as shown in fig. A-1. The total movement of the outer ring when the balls are properly seated in the raceways determines the radial internal clearance. Several readings should be taken using different circumferential orientations of the rings to get a comprehensive average reading. A B fig. A-1. Radial internal clearance. A and B are applied forces. TABlE A-2. liMiTs fOR RADiAl iNTERNAl ClEARANCE Of SINGLE-ROW RADIAL CONTACT BALL BEARINGS UNDER NO LOAD (APPliEs TO BEARiNgs Of ABEC1 AND ABEC3 TOlERANCEs) All tolerances in micrometers (m) and ten-thousandths inches (0.0001 in.) TimkenPrefix (ABMA designation) H (C2) Acceptance Limits R (C0) Acceptance Limits (1) P (C3) Acceptance Limits (1) J (C4) Acceptance Limits JJ (C5) Acceptance Limits Basic Bore Dia. Over Incl. Low High Low High Low High Low High Low High mm mm in. 2.5 10 0 7 2 13 8 23 14 29 20 37 0 3 1 5 3 9 6 11 8 15 10 18 0 9 3 18 11 25 18 33 25 45 0 3.5 1 7 4 10 7 13 10 18 18 24 0 10 5 20 13 28 20 36 28 48 0 4 2 8 5 11 8 14 11 19 24 30 1 11 5 20 13 28 23 41 30 53 0.5 4.5 2 8 5 11 9 16 12 21 30 40 1 11 6 20 15 33 28 46 40 64 0.5 4.5 2 8 6 13 11 18 16 25 40 50 1 11 6 23 18 36 30 51 45 73 0.5 4.5 2.5 9 7 14 12 20 18 29 50 65 1 15 8 28 23 43 38 61 55 90 0.5 6 3.5 11 9 17 15 24 22 35 65 80 1 15 10 30 25 51 46 71 65 105 0.5 6 4 12 10 20 18 28 26 41 80 100 1 18 12 36 30 58 53 84 75 120 0.5 7 4.5 14 12 23 21 33 30 47 100 120 2 20 15 41 36 66 61 97 90 140 1 8 6 16 14 26 24 38 35 55 120 140 2 23 18 48 41 81 71 114 105 160 1 9 7 19 16 32 28 45 41 63 140 160 2 23 18 53 46 91 81 130 120 180 1 9 7 21 18 36 32 51 47 71 160 180 2 25 20 61 53 102 91 147 135 200 1 10 8 24 21 40 36 58 53 79 180 200 2 30 25 71 63 117 107 163 150 230 1 12 10 28 25 46 42 64 59 91 200 240 3 36 30 81 74 137 127 193 183 267 1 14 12 32 29 54 50 76 72 105 240 280 3 41 33 97 86 157 147 224 213 310 1 16 13 38 34 62 58 88 84 122 280 320 5 48 41 114 104 180 170 257 246 353 2 19 16 45 41 71 67 101 97 139 320 370 5 53 46 127 117 208 198 295 284 409 2 21 18 50 46 82 78 116 112 161 370 430 8 64 56 147 137 241 231 340 330 475 3 25 22 58 54 95 91 134 130 187 430 500 10 74 66 170 160 279 269 396 386 551 4 29 26 67 63 110 106 156 152 217 500 570 10 81 74 193 183 318 307 450 439 630 4 32 29 76 72 125 121 177 173 248 570 640 13 91 85 216 206 356 345 505 495 706 5 36 33 85 81 140 136 199 195 278 640 710 20 114 107 239 229 394 384 564 554 780 8 45 42 94 90 155 151 222 218 307 710 800 20 140 130 269 259 445 434 630 620 879 8 55 51 106 102 175 171 248 244 346 800 1060 28 211 201 353 345 587 577 833 823 1148 11 83 79 139 136 231 227 328 324 452 (1) Standard fits for Timken radial ball bearings. P(C3) for bearing O.D. greater than 52 mm (greater than 25 mm bore).

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