What Is an Air Spring?
An air spring is a shock-absorbing device that uses compressed air and rubber elasticity. It offers higher damping capacity compared to metal springs and maintains damping force consistently under varying loads. These springs are durable, with excellent shock and vibration resistance, and are adaptable to load fluctuations, though they are costlier and more complex in design and maintenance than metal springs due to components like air compressors and air piping.
Uses of Air Springs
Air springs are widely used in various applications, particularly in vehicle suspensions and seismic isolation devices for buildings:
1. Vehicles
Employed in high-end vehicle suspensions for superior ride quality, they are also used in cargo transport vehicles and bullet train cars. Air springs provide enhanced comfort and NVH (noise, vibration, and rattling) performance.
In dual rear axle vehicles, they are used to increase drive wheel surface pressure in challenging conditions like snowy or muddy roads by lifting the rear axle.
2. Buildings
Used in building foundations or structures to absorb earthquake vibrations and ensure stability.
Principle of Air Spring
Air Springs function by changing air pressure and volume in a special rubber bag. The stiffness of the spring is adjusted by varying the compressed air amount, providing flexibility and vibration absorption during operation.
Challenges include potential rupture under overload, air leakage due to deterioration, and displacement risks during rapid damping. In vehicle suspensions, air leaks from moisture intrusion are common.
Types of Air Springs
There are two primary types of air springs based on the rubber film and metal fittings design:
1. Diaphragm Type
This type uses a rubber diaphragm that expands or adjusts pressure according to the load, enhancing ride comfort and vehicle stability.
2. Bellows Type
Employing rubber bellows (corrugated), these are commonly used in large vehicles like trucks and buses, offering durability and adaptability to various loads.