1. There is no change in density, in order to take care of manipulation. Such as: common brand-name shock absorption shrinkage is proportional to impact. It can be predicted that the car will react in bad road conditions. The disadvantage is that the elasticity is relatively stiff and the impact is not good enough. But having said that, it is impossible to solve this problem with the best damping spring to run the bad road.
2. The denser type can improve the ability to deal with sharp objects. The impact starts from the lower end of the spring, so the lower end should be denser and the upper end should be sparser. Ideally, the denser the spring and the smaller the deformation per unit length under the same total deformation, the smaller the total stress (soft). The large contraction when encountering large and short impacts can prevent this force from being transmitted to it. The fully dense spring is too crowded and affects the maximum contraction length. As long as the impact is filtered out at first, the rest is not so severe, and the upper spring can be taken care of, which will not affect the adaptability and improve the contraction stroke.