How Air Springs Work in a Vehicle
Air springs are heavy duty torsion bars coiled around an axis which compress and expand to absorb motion of the wheels. They consist of several layers of metal bound together which function as a single unit. They are used in car suspension systems and are they are considered more efficient in vibration isolation than steel springs. Air springs are useful to the air suspension system of a vehicle as they offer a smooth ride and they assist in leveling.
Types of Air Springs
Air springs are classified as convoluted or reversible sleeves. Both categories operate using the same principle. One of the main differences between the 2 types of air springs is that reversible sleeves have a piston as an additional component on the device that is not found in convoluted types.
Mechanism of an Air Spring
When air fills the cylindrical chamber in an air spring, it compresses which causes an increase in pressure. When the air spring is extended, air comes out of the chamber which causes a decrease in pressure. The mechanism where air fills or empties the chamber allows the air spring to automatically return to neutral. This is the height the car is set to ride at as it experiences disturbances in the driving force.
Air springs that function on the principal of a pneumatic system consist of a cylindrical chamber of air which is positioned between the wheel and the car’s body. The compressive property of air is useful in absorbing the wheel’s vibration. However, pneumatic systems are associated with frequent malfunctions as the compressor does not always work as expected. The reason is that any holes in the air spring bring about a loss of the vehicle’s height as well as ground clearance.
Parts of an Air Spring
Reversible sleeve air springs consist of a piston which is not found in convoluted air springs. It plunges in and out of the air cavity within the cylindrical chamber. Pistons are attached to the moving trail arm or axle mount.
Other components of air springs include bead plates which provide a firm attachment to mounting surfaces. The sleeve or fabric-reinforced rubber bellow is the component that contains air.
Benefits of Air Springs vs. Steel Leaves
One of the main advantages of air springs is that they provide variable load carrying capability. Changes in air pressure make it possible to carry loads which can be adjusted over a wide range without changing its height.
It is also possible to change the spring rate without altering the height of the air spring. This is possible through changing air pressure. In steel springs, a change in height would require replacing the component in the car.
The use of air pressure from the compressor makes it easy to maintain and control the height of the air spring. This allows useful capabilities such as load leveling and squatting which are difficult to achieve using steel springs.
The bellow which is made from fabric-reinforced rubber is flexible which provides low friction action. The material reduces friction between rigid attachment points to the frame and suspension.