Comparison of life calculations for oscillating bearings. 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. Calculate the bearing capacity factors and the maximum load of a pier apply to mechanical engineering perform using shear strength, vertical stress, density, bearing capacity, merrit handbook, maximum load, etc. Table5 shows calculation example of load distribution. The programme provides solutions to the following tasks. The bearings have a build in pretension which is further increased by mounting and temperature. Considering the load distribution within the bearing, clearance and tilting angle will affect the resulting bearing life. The drawing displayed is only for general representation and may not be identical to the selected bearing variant. This fact is very important in estimating bearing service life for applications using two or more bearings. 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 predetermined size criterion. Calculation software free download calculation top 4. This allowed the calculation to include bearing reliability. The skf bearing calculator makes it easy to perform complex bearing calculations.
Service life of oiles bearings depends on application atmosphere and other relevant conditions. A criterion for gearbox design and reliability optimization. For such applications skf provides readygreased bearings and bearing units with integral seals or shields, which are suitable for maintenancefree operation. The bearing life is calculated using the load distribution on each rolling element and is therefore. The skf formula for rolling bearing life evolution online. Pdf comparison of life calculations for oscillating. Antonio gabelli, armel doyer and guillermo moralesespejel. A tutorial for the calculation of multiple cylindrical. With this app you can calculate rated bearing and grease life or search for other. Calculation software free download calculation top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices.
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. Mitcalc rolling bearings calculation ii free download. This module can be used for the selection, calculation and check of rolling bearings. The skf bearing calculator makes it easy to perform complex bearing calculations,with this app you can calculate rated bearing and grease life or search for. Hi, im after a bit of assistance with a calculation for a wind turbine generator bearing. Rolling bearing life prediction, theory, and application erwin v. Operating life the operating life is the life actually achieved by a plain bearing. Calculation of service life basic bearing knowledge. 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. Life adjustment factor for ball bearing material a 2 life adjustment factor for application conditions a 2.
Calculation of bearing life according iso 281 and isots 16281. 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. Bearing life calculation for a windturbine generator. The ibutton before each calculation gives more information about the theory behind the calculation. Below formula is determined from the relationship between the load and the sliding distance and should be regarded as rough standard for designing. The rolling bearing analysis software is calculating the life of rolling bearings according isots 16281 considering the inner geometry of the bearing. Bearing life is commonly defined in terms of l10 life, which is sometimes referred to as b10. Calculation of service life basic bearing knowledge koyo. Mesys offers standard software for shaft and bearing analysis and develops custom. With this app you can calculate rated bearing and grease life or search for other information like. The mesys rolling bearing calculation determines the load distribution within the bearing and the bearing life according isots 16281.
Depending on the life calculation method used, the bearing ratings have to be selected accordingly. Mitcalc rolling bearings calculation ii free download version. Calculate bearing life maintenance worldmaintenance world. Bearing life calculated by the bearing technical calculation tool is basic rating life. The l10 preload life of a bearing is normally adjusted as follows, according to realworld operating conditions. The basic life formula, also know as the l10 life formula is used to calculate the number of revolutions before a failure occurs.
For such applications skf provides readygreased bearings and bearing units with integral seals or shields, which are suitable for maintenance free operation. L10 bearing life calculator bearing design, manufacture and. 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. The formulas are simply a guideline and should no be relied upon for critical applications. Present standards for bearing life calculation are based on work carried out at skf in 1947 by gustaf lundberg and arvid palmgren. The basic rating life of a bearing according to iso 281 is where. Ntn corporation bearing technical calculation tool. Ball bearing fatigue life calculator using equivalent radial load. Ball and roller bearings cad data of model numbers given in the catalog is available as an electronic catalog. Ball bearings fatigue life and load ratings calculator. A detailed description of rating life calculation is given in catalogue hg 1, plain bearings. Perform calculations and searches for skf bearing products wherever you are. P equivalent load n the basic fatigue life of a rotating deepgroove ball bearing is given as.
In the case of single row ball bearings and where a, a2, a3 can be considered equal to one, the equations may be simplified as follows. In the following example the rating life and expanded modi ed rating life are to be calculated. For radial bearings, this load is expressed as pure. The task is to change the spreadsheet so that it uses iso data, and not the timken data that it currently uses for the calculation. Ball bearing fatigue life calculator using equivalent. For radial bearings, this load is expressed as pure radial load and is called the dynamic equivalent radial load. This section contains the bearing data that is needed for calculating the load and life of rolling element bearings, including 1.
Engineers typically learn that the bearing l10 life can be estimated using the so called cp method or the basic rating life of the bearing, a method rooted in the 1940s. Here is the official description for mitcalc rolling bearings calculation ii. Clearance of the bearing is the amount of free shift of one ring against the other from one margin position to the other. Ball bearings fatigue life calculations and load ratings.
The rolling bearing analysis software calculates the life of rolling bearings according isots 16281 considering the inner geometry of the bearing. 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. Skf bearing calculator for ios free download and software. Using apkpure app to upgrade skf bearing calculator, fast, free and save your internet data. Therefore the influence of tilting angles or bearing clearance on bearing life can be evaluated. The c r rating, based on one million revolutions, is used for the iso method, and the c 90 rating, based on 90 million revolutions, is utilized for the timken method. Please feel free to contact us by phone andor email. Comparison of life calculations for oscillating bearings considering individual pitch control in wind turbines. Download mitcalc rolling bearings calculation skf select, document, and calculate various aspects of skf rollingbearings for your.
L10 bearing life calculator bearing design, manufacture. Rolling bearing calculation according isots 16281 the bearing life calculation according isots 16281 2008 is the latest standardized version of a bearing life calculation. If handled, mounted, maintained, lubricated and used in the right way, the life of the bearing will normally reach and even exceed the calculated l 10 life. Formula for basic rating life described above is applied to bearings whose. Grease life in lubricatedforlife deep groove ball bearings.
The equation suggests that the rating life of these bearings as a system becomes shorter than that of the bearing with the shorter life. 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. I have performed the calculation by hand for other plant before, but obviously the wind turbine operates at a constantly varying rpm, and despite contacting skf and searching every handbook and engineering reference in my library i still cant find a guideline on where to start with anything other than a. Download mitcalc rolling bearings calculation skf 1. Elastic deformation in the bearing, axlebox housing or bogie frame components are not considered in the basic rating life calculation. A more comprehensive evaluation of the experimental data also indicated that the total bias in life calculation could be reduced by half using the skf life equation in comparison to the results of life calculations based only on bearing standard ratings. Usage method 1596kb instructions for use, disclaimer, etc.
It may deviate from the calculated basic rating life. When relubrication calculation is selected along with bearing life, only grease can be selected as lubrication. Bearing capacity and maximum load of a pier ptc community. Calculation of paired angular contact bearings a pair of angular contact ball bearings mounted backtoback should be calculated for a load case radial load only, and a second load case tilting moment only. The duration of this warranty is one year from date of delivery. Calculation example rolling bearings according to to din iso 281. After our trial and test, the software was found to be official, secure and free. Published under licence by iop publishing ltd journal of physics. The following calculations are available in the skf bearing calculator. Adequate bearing spread for load accommodation is achieved by mounting either two bearings or one doublerow bearing. Calculation example rolling bearings according to to din.
Skf bearing calculator for android download apk free. I have been given an excel spreadsheet which performs the l10 bearing life calculation for a series of different bearings that our company uses. Calculate bearing life maintenance worldmaintenance. Shaft strength calculation bearing rating life and inner geometry assessment of. Ball bearings fatigue life calculations and load ratings calculation and equations. Influence of load and lubricant viscosity on adjusted reference speed. Price and delivery time are indicated for the selected product. Any downloading, reproduction, use, reprinting and adaptation of the. 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. F schwack 1, m stammler 2, g poll 1 and a reuter 2. The appropriate shaft is indicated with price and delivery time. 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. Convert b10 or l10 bearing life to mtbf mean time between. Bearing calculation formulas inventor 2019 autodesk.
But, others are available, or you could work out the equations by hand or in a spreadsheet program. The life equation was formulated using the weibull probability theory of fatigue developed in 1936. Bearings application knowledge menu ball bearings suppliers bearings and bushings products and supply. 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. Adequate bearing spread for load accommodation is achieved by mounting either two bearings or one. Mitcalcroler bearings fag free version download for pc. The basic rating life for radial ball bearing is given by. This download was checked by our builtin antivirus and was rated as safe. Ball bearings fatigue life calculations and load ratings calculation. In many greaselubricated bearing applications, the service life of the grease exceeds the bearing life, so that no grease needs to be added during the bearing life. Demo versions for shaft and rolling bearing analysis are available here.
As well, resulting moments on the bearing due to elastic deflection of shaft, axlebox or suspension are not taken into account. Demo versions and documentation are available under downloads. With this app you can calculate rated bearing and grease life or search for other information like bearing frequencies or shaft and housing fits. Converting b10 or l10 bearing life to mtbf mean time between failures for this demonstration, i am going to reference the use of the true progress free weibull reliability calculator, which you can download by following this link. Life can vary considerably, it is affected by many variables that the formulas cannot account for. Applied calculation examples basic bearing knowledge koyo. Skf bearing calculator perform calculations and searches for skf bearing.
These bearing failures can be minimized by selecting the proper mounting method and lubricant, as well as the bearing most suitable for the application. Click on the continue button to move on to enter input parameters. As well, resulting moments on the bearing due to elastic deflection of shaft, axlebox or. The method is applied to bearing life calculation for a mechanical application in order to prove the suitability of the proposed method for doublerow bearings or. 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. When calculating the load components for a single bearing, the axle journal is considered as a beam resting on rigid, momentfree bearing supports. The generated report can be downloaded for future reference. To learn more about how you can help engineers edge remain a free resource and not see advertising or this message, please visit membership. 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. Example 1 bearing service life time with 90 % reliability. Bearing is defined by websters to be a support or supporting part a bearing is a component that allows for relative motion between parts your skeleton is the central structure that supports your body your bodys joints are bearings that allow different parts to move bearings can have many forms, but only two types. Bearing life is essentially a fatigue phenomenon of surface layer which is subjected to repeating cyclic load. Rolling bearing life prediction, theory, and application.
190 616 491 1112 783 1423 1473 1321 866 80 941 1181 930 563 667 1319 408 957 801 540 502 1169 1015 1293 1494 1175 1390 852 591 659 269 514 898 1248 433 816 724 212 1007