fig, it is first necessaryto calculate the basic rating life for the individual time periods using mean values of the load and the sliding vel- ocity for the individual time periods. When this has been done, the total basic rating life can be calculatedusing the following equation

1

Product information

2

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3

Product data Page ................4 fig the individual basic rating lifecan be calculated using the constant values of p and v. However, when the load and sliding velocity are not con- stant (b) in Basic rating life Page ..............57 Calculation examples

Variable load and sliding velocity

1G
h = –––––––––––––––––––––––t

Calculation examples

If, during operation, the load and/or thesliding velocity change it is first neces- sary to calculate individual rating lives for the periods of constant load and sliding velocity, before the basic rating lifecan be calculated. If the load and sliding velocity occur as shown by (a) in –––––+–––––+––––– +…T G
1 t
2 t
3 The calculation examples shown in the following serve to illustrate themethods used to calculate the requis-ite bearing size or the basic rating life for spherical plain bearings manufacturer and rod ends.Using the SKF Interactive Engin-eering Catalogue which incorporates programs to do these and many other calculations, results will be obtained quickly and accurately. Additionally, the programs can be run any number of times to enable the best possible solu- tion to be obtained.The SKF Interactive EngineeringCatalogue is available on CD-ROM or online at www.skf.com.
h1 T G
h2 T G
h3 whereG
h =total basic rating life, operat-ing hours t
12 1 , t
2 …=time during which p
1 and v
1 , p
2 and v
2 etc. pertain, hT=total duration of one cycle (= t
12 1 + t
2 + t
3 + …), h G
h1 …=individual values of rating lifefor conditions p
1 and v
1 , p
2 and v
2 etc., operating hours
Alternating load and variable sliding velocity Fig 12 vpvp p 2 vpvp 1 v v 2 v 2 31 1 p 1 p 3 p 2 4 v 3 v 4 1 1 p 3 t t 2 t 3 tt 4 t t 2 tt 3 a T b T 30