Air spring is a kind of cord reinforced rubber capsule, filled with compressed air, using the compressibility of gas to play the role of spring damping rubber products, there are long pillow type, gourd type and diaphragm type.  
Used on automobile air spring can be roughly divided into free film type, hybrid, and capsule type air spring sleeve type, its structure and tubeless tyre rubber capsule, by inside rubber (air layer), rubber, fabric reinforced layer and steel wire circle, its load is mainly composed of cord, cord material is air spring pressure resistance and durability of the decisive factor,  The general use of high strength polyester cord or nylon cord, cord layer number is generally 2 or 4 layers, layers crossed and the direction of the capsule into an Angle arrangement.  
Compared with metal spring, it has the advantages of small mass, good comfort, fatigue resistance, long service life and so on. It also has the effect of shock absorption and noise elimination.  Air spring shock absorber is widely used in automobiles, truck ,trains, presses and other machinery.