This paper presents information on new technology which has made the Composite Coil Spring a practical Reality. The light weight and low cost nature of this novel component presents very interesting possibilities for reducing the weight of automotive models.
The experimentation with composite materials which was focused on developing practical components with viable manufacturing methods began in our company 1983. The first episode was with very strong torsion members for truck applications. This was followed by development of a unique “C” spring design in 1993 (reported in SAE paper
2000-01-0100). This paper deals with the new successor to these earlier designs, the “Composite Coil Spring”.
This paper identifies the manufacturing process that has been developed and patented to provide composite Coil springs cost effectively. The paper also presents the physical properties of the springs which are made from thermoset Epoxy, and E type glass fibers. The spring rate, creep and fatigue measurement results are presented. The remarkably longer fatigue life is made possible by the unique fiber positioning which is done via a numerically controlled patented machine. This manufacturing process provides for very good quality control, and also cost effective manufacture of the Composite Coil Spring.
The weight saving in many applications is typically 75% of the steel spring. The economic manufacturing method used has provided, in several case studies, cost savings over the steel springs. The robust design also requires no coating to protect it from environmental attack or rock damage.