4. Torsion bar springs
A torsion bar spring (usually simply called a torsion bar) is a spring-steel rod that uses its torsional elasticity to resist twisting. One end of the torsion- bar is anchored to the frame or other structural member of the body, and the other end to a component that is subjected a torsional load. Torsion bar springs are also used to make stabilizer bars. Characteristics:
- Since the energy absorption rate per unit of weight is great as compared to other springs, the suspension can be lightened.
- The layout of the suspension system is simplified.
- As with coil springs, torsion bar springs do not control oscillation, so it is necessary to use shock absorbers along with them.
5. Rubber springs
Rubber springs absorb oscillations through the generation of internal friction when they are deformed by an external force. Characteristics:
- They can be made in any shape.
- They are silent during use
- They are not appropriate for use in supporting heavy loads. Therefore, rubber springs are used mainly as auxiliary springs or as bushings, spacers, cushions, stoppers and other supports for the suspension components.
6. Air springs
Air springs make use of the fact that air has elasticity or “springiness” when compressed. Characteristics:
- They are extremely soft when the vehicle is not loaded, but their spring constant can be increased as the load is increased by increasing the air pressure inside the chamber. This provides optimum riding comfort both when the vehicle is lightly loaded, and when it is fully loaded.
- The height of the vehicle can be kept constant, even if the load changes, by adjusting the air pressure. However, in air suspensions using air springs, devices for controlling the air pressure and compressors for compressing air, etc., are necessary, so the suspension becomes complex. Currently, the electronically-modulated air suspension, which incorporates this type of air spring, is offered as an option in some models.