Bearing speed is limited primarily by internal friction bearing temperature rise caused by heat , when the speed exceeds a certain threshold , the bearing due to burns and can not continue to rotate . Bearing speed limit which do not generate heat and can cause friction burns continuous rotation of the limit value .
Therefore , bearing speed limit depends on the type of bearing , size and accuracy as well as lubrication, lubricant quality and quantity , and type of materials to maintain a variety of factors , such as load conditions rack . All kinds of bearings with grease lubrication speed limit and oil lubrication ( oil bath lubrication ) when the size of the bearings are set out in the table , the values expressed in the general standard design bearing load conditions (C / P> = 13, Fa / Fr <= rotation about 0.25 ) of the speed limit value . Further , the lubricant according to the different types and grades , although better than the other may also be used for high-speed rotation but not performance .
Correction speed limit load conditions C / P <( that is about equivalent dynamic load P exceeds the basic dynamic load rating C 8% ) 13 or under synthetic load axial load exceeds 25% of the radial load , the use the formula for the speed limit to be amended. na = f1 * f2 * n here na: revised speed limit , rpm f1: and load conditions relating to the correction factor f2: Synthetic load associated with the correction factor n: speed limit under normal load conditions , rpm ( reference bearing size limit axial load , N {kgf} ball bearings with seals : Table ) C: basic dynamic load , N {kgf} P: equivalent dynamic load , N {kgf} Fr: radial load , N {kgf} Fa speed with contact seals (RS type ) ball bearing speed limit is restricted seal contact surface line speed , allowing the line speed depends on the rubber seals .
Precautions during high-speed rotation of the bearing rotating at high speed , especially speed close to or exceeding the speed limit according to the size of the table , the main should note the following:
( 1 ) the use of precision bearings
( 2 ) analysis of the bearing internal clearance ( internal bearing clearance to consider reducing the amount of temperature rise generated )
( 3 ) Analysis of the cage type material ( for high-speed rotation, suitable for cutting copper alloy or phenolic resin cage . There is also applicable to high-speed rotation of the synthetic resin molded cage )
( 4 ) Analysis of Lubrication ( used for high-speed rotation of the circulation lubrication , spray lubrication , oil mist lubrication and oil lubrication, lubrication ) coefficient of friction bearing ( reference ) In order to facilitate comparison with the sliding bearing , the bearing may be a rolling bearing friction torque inside diameter is calculated by the following formula : M = uPd / 2 where M: friction torque , mN.m {kgf.mm} u: coefficient of friction , bearing load , N {kgf} d: nominal bearing bore diameter , mm friction coefficient u by bearing Type , affecting the bearing load , speed, lubrication and the like.
Therefore , bearing speed limit depends on the type of bearing , size and accuracy as well as lubrication, lubricant quality and quantity , and type of materials to maintain a variety of factors , such as load conditions rack . All kinds of bearings with grease lubrication speed limit and oil lubrication ( oil bath lubrication ) when the size of the bearings are set out in the table , the values expressed in the general standard design bearing load conditions (C / P> = 13, Fa / Fr <= rotation about 0.25 ) of the speed limit value . Further , the lubricant according to the different types and grades , although better than the other may also be used for high-speed rotation but not performance .
Correction speed limit load conditions C / P <( that is about equivalent dynamic load P exceeds the basic dynamic load rating C 8% ) 13 or under synthetic load axial load exceeds 25% of the radial load , the use the formula for the speed limit to be amended. na = f1 * f2 * n here na: revised speed limit , rpm f1: and load conditions relating to the correction factor f2: Synthetic load associated with the correction factor n: speed limit under normal load conditions , rpm ( reference bearing size limit axial load , N {kgf} ball bearings with seals : Table ) C: basic dynamic load , N {kgf} P: equivalent dynamic load , N {kgf} Fr: radial load , N {kgf} Fa speed with contact seals (RS type ) ball bearing speed limit is restricted seal contact surface line speed , allowing the line speed depends on the rubber seals .
Precautions during high-speed rotation of the bearing rotating at high speed , especially speed close to or exceeding the speed limit according to the size of the table , the main should note the following:
( 1 ) the use of precision bearings
( 2 ) analysis of the bearing internal clearance ( internal bearing clearance to consider reducing the amount of temperature rise generated )
( 3 ) Analysis of the cage type material ( for high-speed rotation, suitable for cutting copper alloy or phenolic resin cage . There is also applicable to high-speed rotation of the synthetic resin molded cage )
( 4 ) Analysis of Lubrication ( used for high-speed rotation of the circulation lubrication , spray lubrication , oil mist lubrication and oil lubrication, lubrication ) coefficient of friction bearing ( reference ) In order to facilitate comparison with the sliding bearing , the bearing may be a rolling bearing friction torque inside diameter is calculated by the following formula : M = uPd / 2 where M: friction torque , mN.m {kgf.mm} u: coefficient of friction , bearing load , N {kgf} d: nominal bearing bore diameter , mm friction coefficient u by bearing Type , affecting the bearing load , speed, lubrication and the like.
