Design information for engineers, such as spring calculation formulas,
which are the basis of spring design, can be found here.
The permissible stress should be within the elastic limit of the material. If the surface condition is good, the maximum static stress should be 70% or less of the tensile strength.
The permissible bending stress should be determined in consideration of various factors that affect fatigue strength such as stress conditions, number of repetitions, and usage environment. When subject to a repeated load, the following as a guide for estimation. If the maximum / minimum stresses and tensile strength are known using the diagram for bending stress and fatigue strength below, it is possible to calculate γ = σmin / σmax and the upper limit stress coefficient (σmax / σB) or lower limit stress coefficient (σmin / σB) and estimate the service life from the intersection in the figure. (However, this diagram cannot be used for stainless steel strips and phosphor bronze plates. Please contact us directly for further details.)