Design information for engineers, such as spring calculation formulas,
which are the basis of spring design, can be found here.
For example, when the following conditions are given, the material diameter, number of active coils, spring constant, and stress can be calculated as follows.
When P = 9,000 N, we will design a compression coil spring of = 30 mm, = 290 Mpa, D = 100 mm, Hf = 200 mm. The permissible stress is 550 Mpa or less.
Therefore, the stress of this spring at 9,000 N is equal to or less than the permissible stress.