Hello.
It is said that the normal stress of a compression coil spring that receives a static load should be 80% or less of the maximum allowable stress, but is it okay to set the maximum stress of 80% or less of the maximum allowable stress for a compression coil spring receiving dynamic load too? (corrected stress τmax because it is a dynamic load). In that case, is there any problem in setting the stress at maximum compression to a value close to the maximum allowable stress (99.999…%), exceeding the recommended value of 80%?
Thank you for your inquiry, 694!
When subjected to repeated load, the allowable stress must be determined in consideration of stress concentration, average stress and stress amplitude, and surface condition.
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Thank you!
Even with a compression coil spring used under a static load, the stress at the specified height still have to be 80% or less of the allowable stress.
If the stress is within the permissible torsional stress (less than 100%) and will not cause permanent deformation, is it still recommended that the stress is 80% or less of the allowable stress for the safety reason.
However, in this case, the stress at the solid height exceeded the allowable stress.
So the question here is: is there any problems even if you don’t press the spring to the solid height?
Example. SUS304WPB, d=1.4, D=6.4, Na=4 Free height = 12.2
Mounting (designated) height = 8.8
Solid height = 7.7 (close end, grinding)
with all the above conditions,
τ0 = 633.79N/mm2> Allowable stress 624 N/mm2 (approx. 780 x 0.8) NG?
τ (close contact) = 838.84 N/mm2> 624 N/mm2 NG?
Hello! In the case of static load, the stress should be 80% or less of the allowable stress. Also, there is no problem with the dimensional specifications that you sent us.
Please set it with allowable stress.
* Setting: In the final step of the spring making process, high stress over the elastic limit of the material is applied to the direction of use for the spring that has been molded and heat treated. A type of plastic working.
