Fits and Clearances - bearing

1 fits and Clearances Pocket Guide fits and Internal Clearances fits Importance of Proper fits In the case of a rolling bearing with the inner ring fitted to the shaft with only interference, a harmful circumferential slipping may occur between the inner ring and shaft. This slipping of the inner ring, which is called creep , results in a circumferential displacement of the ring relative to the shaft if the interference fit is not sufficiently tight. When creep occurs, the fitted surfaces become abraded, causing wear and considerable damage to the shaft. Abnormal heating and vibration may also occur due to abrasive metallic particles entering the interior of the bearing . It is important to prevent creep by having sufficient interference to firmly secure that ring which rotates to either shaft or housing. Creep cannot always be eliminated using only axial tightening throughout the bearing ring faces. Generally, it is not necessary, however, to provide interference for rings subjected only to stationary loads.

2 fits are sometimes made without any interference for either the inner or outer ring, to accommodate certain operating conditions, or to facilitate mounting and dismounting. In this case, to prevent damage to the fitting surfaces due to creep, lubrication or other applicable methods should be considered. 1. Loading Conditions and fits bearing Operation Load fits Load Application Inner Ring Outer Ring Conditions Inner Ring Outer Ring Rotating Stationary LOAD Rotating Stationary Inner Ring Load Tight Fit Loose Fit LOAD Rotating Stationary Outer Ring Load Stationary Rotating Stationary Rotating Rotating Outer LOAD Stationary Ring Load Loose Fit Tight Fit Stationary Inner Ring Load Rotating Stationary LOAD. Rotating Direction of Rotating or Rotating or Direction of load indeterminate due to variation of direction or unbalanced load Load Tight Fit Tight Fit Stationary Stationary Indeterminate fits and Clearances Pocket Guide 2 3.

3 fits between Radial Bearings and Housing Bores Tolerances for Axial Displacement Load Conditions Examples Remarks Housing Bores of Outer Ring Heavy Loads on bearing Automotive Wheel Hubs in Thin-Walled Housing or (Roller Bearings) Crane Heavy Shock Loads Travelling Wheels P7. Automotive Wheel Rotating Outer Normal or Heavy Loads Hubs (Ball Bearings), Ring Load Vibrating Screens N7. Impossible . Solid Housings Conveyor Rollers, Light or Variable Loads Rope Sheaves, Tension Pulleys M7. Heavy Shock Loads Traction Motors Direction of Pumps, Crankshaft Generally If axial displacement of the Load Normal or Heavy Loads K7 Impossible outer ring is not required. Indeterminate Main Bearings, Medium and Large Axial displacement of outer Normal or Light Loads Possible Motors JS7 (J7) ring is necessary. General bearing Loads of all Kinds Applications, H7. Solid or Split Railway Axleboxes Housings Normal or High Loads Plummer Blocks H8 Easily Possible.

4 High Temperature Rise of Rotating Inner Inner Ring Through Shaft Paper Dryers G7. Ring Load Grinding Spindle Rear Ball Bearings, High- Speed Centrifugal JS6 (J6) Possible Compressor Free Accurate Running Bearings Desirable under Normal For heavy loads, interference or Light Loads Grinding Spindle Front fit tight than K is used. When Direction of Ball Bearings, High- high accuracy is required,very Generally Solid Load Speed Centrifugal K6 Impossible strict tolerances should be Housings Indeterminate Compressor Fixed used for fitting. Bearings Accurate Running and Cylindrical Roller High Rigidity Desirable Bearings for Machine M6 or N6 Impossible Rotating Inner under Variable Loads Tool Main Spindle Ring Load Electrical Home Minimum noise is required Appliances H6 Easily Possible . Remarks 1. This table is applicable to cast iron and steel housings. For housings made of light alloys, the interference should be tighter than in this table.

5 2. Not applicable to special fits . fits and Clearances Pocket Guide 4 5. fits between Radial Bearings and Shafts Shaft Diameter (mm). Cylindrical Tolerance Roller of Remarks Load Conditions Examples Spherical Ball Bearings, Shaft Roller Bearings Tapered Bearings Roller Bearings RADIAL BEARINGS WITH CYLINDRICAL BORES. Easy axial displacement of Wheels on Use g5 and h5 where inner ring on shaft desirable Stationary Axles g6. accuracy is required. Rotating Outer All Shaft Diameters In case of large bearings, Ring Load Easy axial displacement of Tension Pulleys f6 can be used to allow inner ring on shaft unnecessary Rope Sheaves h6 easy axial movement. Electrical Home Appliances, <18 js5. Light Loads Pumps, 18~100 <40 js6 (j6). or Variable Loads Blowers, 100~200 40~140 k6 . (< r) Transport Vehicles, Precision Machinery, 140~200 m6.. Machine Tools <18 js5 (j5-6). General bearing Applications, Medium and Large Motors, 18~100 <40 <40 k5-6.

6 Rotating Inner Normal Loads Turbines, 100~140 40~100 40~65 m5-6 k6 and m6 can be used for Ring Load or ( to Cr) Pumps, single-row tapered roller 140~200 100~140 65~100 m6. Direction of Load Engine Main Bearings, bearings and single-row Indeterminate Gears, 200~280 140~200 100~140 n6 angular contact ball bearings Woodworking Machines 200~400 140~280 p6 instead of k5 and m5. 280~500 r6. over 500 r7. 50~140 50~100 n6. Railway Axleboxes, Heavy Loads Industrial Vehicles, 140~200 100~140 p6. More than CN. or Shock Loads Traction Motors, Over 200 140~200 r6 bearing internal (< r) Construction, clearance is necessary. Equipment, r7. 200~500. Crushers Axial Loads Only All Shaft Diameters js6 (j6) . RADIAL BEARINGS WITH TAPERED BORES AND SLEEVES. IT5 and IT7 mean that the General bearing Applications, H9/IT5 deviation of the shaft from Railway Axleboxes its true geometric from, All Types of Loading All Shaft Diameters roundness and cylindricity Transmission Shafts, should be within the H10/IT7 tolerances of IT5 and IT7.

7 Woodworking Spindles respectively. Remarks This table is applicable only to solid steel shafts fits and Clearances Pocket Guide 6 7. Tolerances for Shaft Diameters Units : m Diameter Single Plane Diameter Mean Classification (mm) Deviation d6 e6 f6 g5 g6 h5 h6 h7 h8 h9 h10 js5 js6 j5 j6 j7 k5 k6 k7 m5 m6 n6 p6 r6 r7 Classification (mm). (Normal). Over incl. dmp Over incl. 0 30 20 10 4 4 0 0 0 0 0 0 + 3 + 6 + 8 + 6 + 9 +13 + 9 + 12 + 16 + 20 + 23 + 27. 3 6 4 3 6. 8 38 28 18 9 12 5 8 12 18 30 48 2 2 4 + 1 + 1 + 1 + 4 + 4 + 8 + 12 + 15 + 15. 0 40 25 13 5 5 0 0 0 0 0 0 + 4 + 7 +10 + 7 +10 + 16 +12 + 15 + 19 + 24 + 28 + 34. 6 10 3 6 10. 8 49 34 22 11 14 6 9 15 22 36 58 2 2 5 + 1 + 1 + 1 + 6 + 6 + 10 + 15 + 19 + 19. 0 50 32 16 6 6 0 0 0 0 0 0 + 5 + 8 +12 + 9 +12 + 19 +15 + 18 + 23 + 29 + 34 + 41. 10 18 4 10 18. 8 61 43 27 14 17 8 11 18 27 43 70 3 3 6 + 1 + 1 + 1 + 7 + 7 + 12 + 18 + 23 + 23. 0 65 40 20 7 7 0 0 0 0 0 0 + 5 + 9 +13 +11 +15 + 23 +17 + 21 + 28 + 35 + 41 + 49.

8 18 30 18 30. 10 78 53 33 16 20 9 13 21 33 52 84 4 4 8 + 2 + 2 + 2 + 8 + 8 + 15 + 22 + 28 + 28. 0 80 50 25 9 9 0 0 0 0 0 0 + 6 +11 +15 +13 +18 + 27 +20 + 25 + 33 + 42 + 50 + 59. 30 50 8 30 50. 12 96 66 41 20 25 11 16 25 39 62 100 5 5 10 + 2 + 2 + 2 + 9 + 9 + 17 + 26 + 34 + 34. + 60 + 71. 50 65. 0 100 60 30 10 10 0 0 0 0 0 0 + 6 +12 +18 +15 +21 + 32 +24 + 30 + 39 + 51 + 41 + 41. 50 80 15 119 79 49 23 29 13 19 30 46 74 120 7 7 12 + 2 + 2 + 2 +11 + 11 + 20 + 32 + 62 + 73. 65 80. + 43 + 43. + 73 + 86. 80 100. 0 120 72 36 12 12 0 0 0 0 0 0 + 6 +13 +20 +18 +25 + 38 +28 + 35 + 45 + 59 + 51 + 51. 80 120 11. 20 142 94 58 27 34 15 22 35 54 87 140 9 9 15 + 3 + 3 + 3 +13 + 13 + 23 + 37 + 76 + 89. 100 120. + 54 + 54. + 88 +103. 120 140. + 63 + 63. 0 145 85 43 14 14 0 0 0 0 0 0 + 7 +14 +22 +21 +28 + 43 +33 + 40 + 52 + 68 + 90 +105. 120 180 9 140 160. 25 170 110 68 32 39 18 25 40 63 100 160 11 11 18 + 3 + 3 + 3 +15 + 15 + 27 + 43 + 65 + 65.

9 + 93 +108. 160 180. + 68 + 68. +106 +123. 180 200. + 77 + 77. 0 170 100 50 15 15 0 0 0 0 0 0 + 7 +16 +25 +24 +33 + 50 +37 + 46 + 60 + 79 +109 +126. 180 250 10 200 225. 30 199 129 79 35 44 20 29 46 72 115 185 13 13 21 + 4 + 4 + 4 +17 + 17 + 31 + 50 + 80 + 80. +113 +130. 225 250. + 84 + 84. +126 +146. 250 280. 0 190 110 56 17 17 0 0 0 0 0 0 + 7 +27 +36 + 56 +43 + 52 + 66 + 88 + 94 + 94. 250 315 16 16 26. 35 222 142 88 40 49 23 32 52 81 130 210 16 + 4 + 4 + 4 +20 + 20 + 34 + 56 +130 +150. 280 315. + 98 + 98. +144 +165. 315 355. 0 210 125 62 18 18 0 0 0 0 0 0 + 7 +29 +29 +40 + 61 +46 + 57 + 73 + 98 +108 +108. 315 400 18 18. 40 246 161 98 43 54 25 36 57 89 140 230 18 28 + 4 + 4 + 4 +21 + 21 + 37 + 62 +150 +171. 355 400. +114 +114. +166 +189. 400 450. 0 230 135 68 20 20 0 0 0 0 0 0 + 7 +31 +32 +45 + 68 +50 + 63 + 80 +108 +126 +126. 400 500 20 20. 45 270 175 108 47 60 27 40 63 97 155 250 20 32 + 5 + 5 + 5 +23 + 23 + 40 + 68 +172 +195.

10 450 500. +132 +132. +194 +220. 500 560. 0 260 145 76 22 0 0 0 0 0 +44 + 70 + 70 + 88 +122 +150 +150. 500 630 22 . 50 304 189 120 66 44 70 110 175 280 0 0 + 26 + 44 + 78 +199 +225. 560 630. +155 +155. +225 +255. 630 710. 0 290 160 80 24 0 0 0 0 0 +50 + 80 + 80 +100 +138 +175 +175. 630 800 25 . 75 340 210 130 74 50 80 125 200 320 0 0 + 30 + 50 + 88 +235 +265. 710 800. +185 +185. +266 +300. 800 900. 0 320 170 86 26 0 0 0 0 0 +56 + 90 + 90 +112 +156 +210 +210. 800 1 000 28 . 100 376 226 142 82 56 90 140 230 360 0 0 + 34 + 56 +100 +276 +310. 900 1 000. +220 +220. +316 +355. 1 000 1 120. 0 350 195 98 28 0 0 0 0 0 +66 +105 +106 +132 +186 +250 +250. 1 000 1 250 33 . 125 416 261 164 94 66 105 165 260 420 0 0 + 40 + 66 +120 +326 +365. 1 120 1 250. +260 +260. +378 +425. 1 250 1 400. 0 390 220 110 30 0 0 0 0 0 +78 +125 +126 +156 +218 +300 +300. 1 250 1 600 39 . 160 468 298 188 108 78 125 195 310 500 0 0 + 48 + 78 +140 +408 +455. 1 400 1 600.