A simple mass on an air spring.
The spring constant of the confined air is:
- γ = adiabatic gas constant
- pa = atmospheric pressure [Nm-2]
- S = cross-sectional area of air column [m2]
- L = length of air column [m]
- The natural frequency is:
- f0 = natural frequency [Hz]
- m = mass [kg]
- A readily attained low system natural frequency for a soft ride and lower shock inputs.
- Almost constant system natural frequency throughout the normal vehicle load range, thus maintaining good ride and lower shock inputs.
- Permits a low system natural frequency for normal road surfaces and improved shock control for the extreme cases.
- The most basic principle utilized is that air is compressible and when compressed, it exerts a force on the structure confining it and that the force exerted is proportional to the pressure.
- Changes in volume of a constant mass of confined air under pressure result in appropriate changes in pressure. P1V1=P2V2 This creates a non-linear spring rate and a nearly constant system frequency in the pressure ranges normally used.
- The ability of the air spring to support a given mass is governed by the effective area and the confined gas pressure.
- The energy storage capacity of air is far greater per unit weight than that of mechanical spring materials (steel or rubber).
See also: Air, Spring Constant.
Subjects: Mechanical Engineering Physics