Each type of bearing has its own niche application area, and thus design engineers must be familiar with different types of bearings, and their applications and limitations. How to determine bearing system life rbi bearing, inc. Click on the download icon to download the report in the. Calculate bearing life maintenance worldmaintenance world. The fatigue life calculation of bearings under rotating conditions has been well researched and standardized. A simplified calculation of a deep groove ball bearing is also available online. Calculation example rolling bearings according to to din iso 281. Bearing calculation calculation of the bearings basic rating life according to iso 281. Bearing life calculating the basic fatigue life expectancy of rolling bearings. Basic rating life for simplified calculations and to obtain an approximate value of the bearing life, the socalled handbook method is used to calculate the basic rating life. Applied calculation examples basic bearing knowledge koyo. Using technical calculation, you will be guided through a series of selection stages allowing you to select the most appropriate bearing for your application.
Select one of the items below and click the update button. Example 7 calculation of allowable axial load for cylindrical roller bearings conditions singlerow cylindrical roller bearing. Bearing lubrication 2wbcnt how to determine bearing system life. In the case of needle bearing, its radial type is capable for loading radial load only so that just a radial load will be applied. Rolling bearing calculation according isots 16281 the bearing life calculation according isots 16281 2008 is the latest standardized version of a bearing life calculation. This is the life which 90% of identical bearings subjected to identical usage applications and environments will attain or surpass before bearing material fails from fatigue. Due to a recent update to the thk technical support site, we need you to register some additional information to your optimal product selection tool account. Demanded life is determined by endurance duration for operating machinery and reliable operating periods. Download mitcalc rolling bearings calculation skf select, document, and calculate various aspects of skf rollingbearings for your projects with the help of this excelbased utility.
The check box can be selected to add the calculation result in the report. Shelf life of the greaselubricated bearingcomponent represents the period of time prior to use or installation. The result of a single calculation or multiple calculations can be selected in the report. In addition to the calculation of a single bearing also bearing sets can be considered. Bearing life is essentially a fatigue phenomenon of surface layer which is subjected to repeating cyclic load. Several factors will influence the wear and service life of bushings.
Bushings and plain bearings load capacity and service life. As a result, pitch bearings in wind turbines are designed with different, non standardized approaches. Before their report, every bearing manufacturer calculated life in its own way. The equivalent bearing load has to be calculated based. Only 7 clicks and 4 entries generate a service life result. Figure 348 shows bearing life scatter following a weibull distribution function with a dispersion parameter equal to 1. Rolling bearing life prediction, theory, and application. L bearing life m c bearing dynamic load capacity n f applied dynamic load n.
They are, among others, specific bearing load, sliding speed, pv value, surface roughness of mating parts, mating surface material, and operating temperature. The result of an individual calculation can be deleted by clicking on the delete icon on the right hand side of the respective calculation shown by number 4 in above snapshot. Part number jlm506849 jlm506810, tapered roller bearings. Ball bearings fatigue life calculations and load ratings. Nsk bearing calculation tool bearing life explanation here following three calculation methods are available nsk able forecaster iso 281. Despite the groundbreaking modifications to the old calculation routines, the new methodology was introduced in the skf catalogue 4000 in 1989 ref. The mesys rolling bearing calculation determines the load distribution within the bearing and the bearing life. Calculating life expectancy determines the bearing solution with consideration of bearing material fatigue under defined.
For most calculations, the life is that 90 percent of a group of apparently identical bearings will complete or. May 30, 2019 download mitcalc rolling bearings calculation skf select, document, and calculate various aspects of skf rollingbearings for your projects with the help of this excelbased utility. Kaydon bearing life ratings are not just theoretical computations, like those cited by other manufacturers. Weibull plots are used to compute l10 life and to estimate life for bearings that dont make it to failure. Bearing failures due to fatigue undergo the law of statistic. Comparison of life calculations for oscillating bearings. And for recirculating bearings with rollers as the loadcarrying elements, the equation is. Even easier, faster product selection and servicelife calculation. Life can vary considerably, it is affected by many variables that the formulas cannot account for. For bearings where it is impossible to test a large number of bearings, the long experience of the timken company will help you in your bearing life calculation. Example 1 bearing service life time with 90 % reliability.
Applied calculation examples basic bearing knowledge. Calculation example rolling bearings according to to din. L nar l 10r a 1 a 2 a 3 or l na l 10 a 1 a 2 a 3 for rating life in hours. The pv value has a considerable influence on the service life of a bushing. The inner geometry of the rolling bearing is provided by the user, but it can also be approximated from the load capacities by the software. The l10 preload life of a bearing is normally adjusted as follows, according to realworld operating conditions. Shelf life shelf life should be distinguished from lubricated bearing component design life as follows. Calculate bearing life maintenance worldmaintenance. L 10 life l 10 life is the life that 90 percent of a group of apparently identical bearings will complete or exceed before the area of spalling reaches the defined 0.
The equivalent bearing load, p, used in the rating life formula, needs to be calculated when combined radial and axial loads occur. As with all other types of machine elements, it is. The basic rating life for radial ball bearing is given by. Globus, gmns ball bearing calculation program, allows for computeraided calculation and the selection from a broad product range in consideration of the life expectancy of various possible solutions. Nup 310 rotational speed n 1500 min1 oil lubrication. Calculation of service life 521 basic dynamic load rating c the basic dynamic load rating is either pure radial for radial bearings or central axial load for thrust bearings of constant magnitude in a constant direction, under which the basic rating life of 1 million revolutions can be obtained, when the inner ring rotates while the outer. Download this related white paper based on five years of actual test results.
Technical calculation is also available online in order for you to perform both simple and more advanced bearing calculations. The selection can be refined further by providing additional information. Zaretsky national aeronautics and space administration glenn research center cleveland, ohio 445 summary a tutorial is presented outlining the evolution, theory, and application of rollingelement bearing life prediction from that. The bearing life is calculated using the load distribution on each rolling element and is therefore. Part number m86649 m86610, tapered roller bearings ts.
The basic rating life of the 6308, using the same steps, is. It was found that the new calculation method could introduce, under certain conditions, a change to the rated life for a factor up to 50 times eq. Ball bearings fatigue life and load ratings calculator. The basic life formula, also know as the l10 life formula is used to calculate the number of revolutions before a failure occurs. Most bearings are selected and sized based on the basic bearing life calculated with and, at times, without life factors. In contrast, for bearings in oscillating applications no international standards exist. Bearing calculation formulas inventor 2019 autodesk. L nar l 10r a 1 a skf f t or l na l 10 a 1 a skf f t for rating life in hours. Bearing life calculation in oscillatory applications. For most calculations, the life is that 90 percent of a group of apparently identical bearings will complete or exceed before the area of spalling reaches. The basic rating life for a specific bearing is based on the basic dynamic load rating according to iso 281. Bearing life testing, fea, failure analysis kaydon bearings. As you will see it in the following, there is more than just one bearing life calculation method, but in all cases the bearing life equation is.
Bearings application knowledge menu ball bearings suppliers bearings and bushings products and supply. General industrial machine manufacturing industry c. Bearing life is essentially the length of time a bearing can be expected to perform. Ball and roller bearings cad data of model numbers given in the catalog is available as an electronic catalog. P equivalent load n the basic fatigue life of a rotating deepgroove ball bearing is given as. Download mitcalc rolling bearings calculation skf 1.
Ntn corporation bearing technical calculation tool. Bearing life is commonly defined in terms of l10 life, which is sometimes referred to as b10. Rolling bearing life prediction, theory, and application erwin v. Suitable iglide materials can be updated with each entry. The shaft calculation allows the calculation of coaxial shaft systems considering nonlinear stiffness of rolling bearings. The calculation returns the pressure distribution between the rolling elements and the reference life according isots 16281 for a given loading force and moment or tilting. The rationale for using the l10 life was first laid down by. The calculation of l10 life for recirculating bearings with balls as the loadcarrying elements, is given by. Usage method 1596kb instructions for use, disclaimer, etc.
Mesys rolling bearing calculation introduction this rolling bearing calculation version 042017, file version 3. Accordingly, where the dynamic equivalent load is p, and rotational speed is n, equation 54 can be used to calculate the basic dynamic load rating c. This life calculation equation does not apply to bearings that are affected by factors such as plastic deformation of the contact surfaces of raceways and rolling. That is why during bearing life calculation the probability of failure is taken into consideration in general, bearing life is calculated with 10% probability of failure, i. The bearing life is calculated using the load distribution on each rolling element and is therefore not limited to an external force but can also consider tilting.
Pdf comparison of life calculations for oscillating. Calculation of service life basic bearing knowledge koyo. This standard covers the calculation of the dynamic basic load rating and basic rating life. For radial bearings, this load is expressed as pure radial load and is called the dynamic equivalent radial load. The bearing industry needed a unified method for calculating bearing life. These illustrations depict a subsurfaceinitiated spall at a hard inclusion and a surfaceinitiated crack network from a surface defect. Fatigue life calculations assume the dispersion in life of identical ball bearings operating under identical conditions, a statistical result is obtained for bearing fatigue life.
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