for new technology network r corporation bearing handling bearings are high precision parts improper handling will lead to premature bearing failure and machine malfunctions care should be taken in the handling of bearings they should be assembled in a clean working environment to ensure that no contaminants infiltrate the bearing and they should be protected from sharp impacts what follows is an explanation of proper bearing handling procedures contents 1 preparations before mounting 2 bearing mounting 3 inspection after mounting 4 bearing removal 5 bearing storage p1 p3 p5 p5 p6
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nd sa ap er 1 preparations before mounting 1.1 bearing mounting surfaces any burrs cutting chips rust or dirt should first be removed from the bearing mounting surfaces installation can then be simplified if the clean surfaces are lubricated with spindle oil burr cutting chip burr cutting chip preparation procedure burr burrs dirt and other contaminants that infiltrate the bearing before and during mounting will cause noise and vibration during subsequent operation contaminant burr p remove any burrs with finegrade sandpaper ste wa remove any dirt and contaminants with a clean paper apply light coating oil contaminant 1.2 mounting equipment ensure that all pressing blocks driving plates hammers and other mounting devices are clean free of burrs and of the correct size 1.4 do not make any modifications to the products bearings are manufactured to very tight tolerances in order to meet extremely high accuracy requirements therefore it is imperative to take special precautions with regard
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2 bearing mounting 2.1 mounting procedures and examples of damage pressing surfaces surfaces with zero pressing load tolerance force applied to inner ring force applied to outer ring mounting on shaft mounting in housing simultaneous mounting on shaft and in housing force applied to outer ring force applied to inner ring force applied to inner and outer rings simultaneously using driving plate force applied to inner or outer ring separately shows inappropriate application of force to inner ring furthermore the maximum static load that bearings can withstand is shown in the ntn catalog as the bearing s basic static load rating this is the maximum amount of force which can be applied to the central contact area between rolling elements and raceway surfaces if exceeded total permanent deformation exceeding 1/10,000 of the bore diameter will result and smooth bearing rotation will be impaired this is the basis for establishing the basic static load ratings damage examples flaking imbeddi
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mounting bearings using a hammer causes damage due to sharp impacts please mount press fit bearings using a pressing arbor or other designed to provide a uniform face 2 bearing mounting 2.2 bearing care bearings are very susceptible to impacts and shock loads bearings carry their loads along an extremely narrow contact surface between the rolling elements and the inner and outer raceway surfaces if an excessive load or impact is applied to this narrow area of contact brinelling and/or scarring will occur this damage leads to objectionable noise and vibration levels and rough bearing rotation even dropping bearings on the floor will cause this type of damage shock load denting/scarring bearings are very susceptible to foreign particle contamination if foreign particles infiltrate the bearing during rotation denting and/or scarring will occur and this will lead to poor bearing rotation and excess noise dust/dirt imbedding denting scarring
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2 bearing mounting 2.3 temperature mounting observe these precautions when heating bearings 1 bearings should never be heated over 120 °c 2 this temperature mounting method cannot be used for pre-greased and sealed bearings or shielded bearings pre-greased bearings ntn amount of inner ring bore diameter expansion 2.4 other heating methods 1 bearing oven bearings are dry this method can also be used for pre-greased bearings when using this method with pre-greased bearings do not heat the bearings above 120°c 2 induction heating this method can also be used for the inner rings of cylindrical roller bearings bearings are dry and can be heated up in a short period of time after using this method administer a demagnetizing treatment to the bearing for more detailed information concerning bearing heating methods,contact ntn tem of h peratu eate re r d be ise d arin iffer gs entia l commonly used for large bearings and bearings with a heavy interference fit 1 immersion of the bearing in heate
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3 inspection after mounting 4 bearing removal to confirm that the bearing has been mounted correctly perform a rotation check 1 first rotate the shaft or housing to see whether anything unusual can be detected 2 next engage the bearing without applying a load after observing its rotational condition at low speed slowly increase the rotational speed and load while checking for any rise in operational noise levels vibrations and temperature 3 if anything unusual is detected during operation stop the bearing and perform an inspection checking for unusual noise or noise levels should be performed by someone familiar with the sound of properly mounted bearings operated under standard conditions in order to avoid damage to machinery and danger to workers when changing or removing bearings proper protective equipment and bearing removal equipment should be used generally speaking reuse of bearings is not recommended if you are considering the reuse of a bearing please read carefully section 2
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5 bearing storage ntn ntn ntn ntn ntn ntn bearings are coated with a rust preventative compound and securely packaged before delivery please observe the following guidelines when storing bearings 1 ideally bearings should be stored in a location with low humidity i.e less than 60 relative humidity 2 bearings should never be stored on the ground but should be stored on shelves or palettes at least 20 cm above the ground 3 boxes of bearings should not be stacked too high or the rust preventative compound may be squeezed out of bearings on the bottom the handling procedures mentioned in these pages represent basic guidelines the observance of these guidelines does not entail all necessary procedures and precautions depending on the type of product specialized handling procedures may also be required fulfillment of a bearing s original performance can be ensured only through the observance of proper handling procedures when necessary please contact ntn to clarify points of uncertainty.
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