BS EN 16984:2016 pdf free.Disc springs-Calculation.
BS EN 16984 When designing springs, friction shall be accounted for. The associated load component is a function ofthe number of single disc springs or elements making up a stack of springs.In this regard, surface finishand lubrication are also of relevance.
Frictional loads act between the conical contact surfaces of the individual springs (factor ww) and thecontact surfaces of the flat plates between the spring is compressed (factor wp).Such loads have theeffect of increasing the spring load when the spring is loaded, and decreasing it when the load isremoved.Formula (20) also accounts for the frictional behaviour of a single disc spring.
Within permissible tolerances, the actual spring will deviate from the geometrically ideal form.In thecase of springs stacked in parallel, such inevitable deviation results in an actual load/deflection curvethat is different from the theoretical curve (and increasingly different as the number of packets makingup the stack increases), particularly in the lower range of the curve.
Since there are residual stresses in the spring as a result of the manufacturing process used, the resultsobtained from Formulae (10) to (14) do not reflect the actual values involved, but rather any nominalvalues.Thus, all information relating to stress in the present standard and in EN 16983:2016, Tables 5to 7, represent these nominal values.
An estimate of the permissible free overall height of the spring, lo, may be based on a determination ofthe design stress ooM, which should be about equal to the tensile strength, Rm, of the material used (formaterials as in EN 16983:2016, max.1 600 MPa).
The most important parameter for springs subject to fatigue loading is the calculated tensile stress onthe bottom side of a single disc spring. This is illustrated in Figure 10, and applies to springs with or without flat bearings.
Springs shall be deemed to be subject to static loading: where such is the only type of loading and where it does not change.BS EN 16984 pdf download.