 నాటియెటి సోతువతురిరంగా, నికులుంపై ముతుతు కూర్లిలా. In this video, I am explaining various design characteristics of rolling contact bearings. At the end of the session, the learners will be able to calculate the dynamic load capacity of the rolling contact bearing. సార్వ్వర్యా. చార్టికాం నికికి. నిమర్లం నాటికాతసిరోలం. ఌతియంనికి. ందరంఖూ మార్లంమం అంత్న్గైనికి. ఎత్రంట్సా. మినాద్యా. వినా the static load capacity is one of the characteristics in which the load acting on the shaft when the shaft is stationary is called as a static load and it is supported by the balls as shown over here as the load p1 p2 p3 etc because of this load there is a deformation between the ball and the recess and this deformation is proportional to applied load so if i go this load goes on increasing this deformation will also increase and if it goes on increasing the performance of the bearing is affected and that's why practically there is a limiting value on the deformation which is allowed and for that it is expected that the maximum deformation at the heavily stressed point that is whatever load out of this maximum that point of contact the deformation is maximum and that should be by past experience it is found that it should be equal to 0.0001 times the ball diameter that is the permissible limit for maximum deformation and corresponding load the bearing can support is called as static load capacity of the bearing so we find by definition the static load carrying capacity of a bearing is defined as the static load which corresponds to a total permanent deformation of balls and recess at the most heavily stressed point of contact and equal to 0.0001 times the diameter of the ball just recall the fatigue failure we know that whenever a component subjected to varying load or fluctuating load and if this load is going to act for large number of cycles then it is prone for fatigue failure the component is subjected to fatigue failure so now for the while and think that whether the balls of the bearing are subjected to fatigue the another important characteristic of bearing is life of bearing the balls and the rollers of the bearings are subjected to variable loads and which are repeated for very large number of cycles in its life and that's why bearings are subjected to fatigue failure so balls and recess are subjected to fatigue failure hence the life of an individual ball bearing is defined as the number of revolutions which the bearing completes successfully before the first sign of fatigue crack in the balls or recess so this is what individual fatigue life we can define and for all the bearings this life varies since the life of single bearing is difficult to predict it is necessary to define the life in terms of statistical average life of group of bearings that means prediction of a single bearing particular life whatever i select is not possible but one can predict the life of 90% group or a statistical average life of a group of bearings and that is something called as retate life of bearing so another term which is been considered as a characteristic of bearing is retate life of bearings and this is defined as retate life of a group of apparently identical ball bearings is defined as the number of revolutions that the 90% of the bearings of a group will complete or exceed before the first sign of fatigue failure means i can consider 10 bearings whatever 9 bearings minimum life so that all 9 bearings will complete that revolution or more than that that particular life i can call retate life of bearing in terms of revolutions and this is been used to predict the life of the bearing so that bearings can be designed for expected fatigue life this retate life is also known as catalogue life l10 or beaten life the life of an individual ball bearing may be different from this retate life because it is for 90% bearing so individual bearing may have some different life the another term we can use is statistically the average life l 50 in which 50% of a group of bearings will complete that particular revolution or exceed it and it is found approximately that the life l 50 that is 50% or average life is five times the retate life that is l10 life this is also called as retate life but it is a retate average life the another important characteristics of the bearing is a dynamic load capacity of bearing it is found that if the load acting on bearing increases the life of bearing decreases and hence the load carrying capacity of bearing is always associated with certain expected fatigue life so the dynamic load is defined considering the expected minimum fatigue life of bearing and that is definition is the dynamic load carrying capacity of bearing is defined as the radial load in case of radial bearings or thrust load in case of thrust bearings that can be carried by 90% of the group of identical bearings for a minimum fatigue life of 1 million revolutions that is 90% bearing should complete 1 million revolution and for that whatever maximum radial load they can withstand that is called as dynamic load carrying capacity of bearing the another term is equivalent bearing load because many times the forces acting on the bearing are having radial components and thrust components that means actually the practical bearing may be subjected to combined load having radial and thrust load it has to be converted into equivalent hypothetical radial load such that whatever life we consider for this hypothetical load will be the same life under practical applications of radial component force and thrust force this equivalent load is defined as the constant radial load in radial bearings which which if applied to the bearing should give the same life as that the bearing will attain under actual condition of forces now to calculate this equivalent load we get this expression p is equal to xvfr plus yfa where p is equivalent dynamic load f r is radial load f a is axial or thrust load v is called as a race rotation factor and v is considered to be 1 if the inner race is rotating that means bearing is mounted on the shaft and v is equal to 1.2 inner race is mounted on the axle that is the outer race is rotating so in such cases we get the value of v and x and y are the radial and thrust factors respectively given by manufacturers catalog now this is the way we can calculate the equivalent load once we get equivalent load for the bearing actually the bearings are subjected to combined load and that is why we calculate equivalent load to calculate the dynamic capacity we make use of this equation that is a expected rated life of the bearing is l10 and it is equal to c by pe raise to k so k is 3 for ball bearings and 10 by 3 for roller bearings so this is the way we can calculate the dynamic capacity of the bearing as a c in which we get equation p l10 raise to 1 by k 3 for ball bearings 1 by 3 and 10 by 3 for roller bearings so it is c is equal to p l10 3 by 10 so this is the way we can calculate the dynamic load capacity of bearing when the bearing is subjected to combined load so by using all such design characteristics we can calculate the required dynamic capacity of the bearing this is my reference thank you