2008 年 2008 巻 53 号 p. 13-19
This paper describes a new coil spring design method for automated, optimized and designer-independent design. In conventional coil spring design, a spring profile at free state is usually designed first and it is then compressed in FEA (Finite Element Analysis) to check if the spring characteristics satisfy the required specifications. However, the spring requirements such as rate, load, FLP (Force Line Position), deformed profile, etc. are usually given at the compressed state of the spring. Therefore, if the result does not meet the requirements, a designer must modify the free state profile while predicting how it reflects to the spring characteristics at deformed state. In the new method, the ideal deformed spring profile is designed first and its corresponded unique free profile is then reversely determined by automated FEA iterations in order to satisfy the requirements. By scanning the total number of turns in a certain range for the deformed spring profile designed at the first stage, the optimal spring design can be selected in terms of weight, stress and manufacturability. This paper validates the new method with actual design example. The method and resultant spring shape are currently international patent pending.