The advantages of using rubber as a means of suspension are :-

1. It can store greater energy per unit weight then the steel. For this reason rubber springing system can be made more compact.

2. The rubber has excellent vibration damping properties.

3. The absence of squeaking which is always present in steel springs.

4. The number of bearings is reduced considerably for the rubber suspension system. This means longer life.

5. Rubber is more reliable. A rubber suspension cannot suddenly fail like the metal springs.



The various types of rubber springs used for vehicles are discussed below :-

1. Compression spring :-

This type of spring is still being used because of the following advantages :-

(i) It is reliable, of simple construction and requires no bonding.

(ii) It provides a rising rate characteristic

(iii) It can resist occasional overload of large magnitude.

(iv) It has a large measure of inherent damping than most types of rubber springs.

However, it's uses is limited because of the fact that some mechanical guide must be provided with this type of spring, and the provision of mechanical guide is generally undesirable.

2. Compression shear spring :-

In this type, the load is carried partly by shear and partly by compression components in the rubber and hence, although large strains may be allowed in the rubber body, shear stress at the bonded faces is kept small and fatigue properties are excellent.

3. Steel reinforced spring :-

Steel reinforced spring ('Eligos' spring) consists of a steel helical spring bonded in a rubber body. The steel springing, though, carrying only about 20% of the load, exercises stabilizing influence on the rubber component thereby allowing a greater stroke/diameter ratio to be used without other forms of guiding.

4. Progressive spring :-

It has initially an exceedingly small rate which rises rapidly as the central cavity closes.

5. Face sheer spring :-

It consists of a thick disc of rubber having metal plates bonded to its flat surfaces, and axially precompressed. It operates by a relative rotation of the plates about its axis thus loading the rubber party in shear.

6. Torsional shear spring :-

It consists of an inner metal shaft, tubular or solid, and an outer trough like shell between which rubber body is bonded, the latter being put under pressure by closing the trough with a riveted or spot welded base plate. The spring operates by the rotation of the shaft about its own axis relative to the shell.