LEVELMOUNT® air suspension elements achieve the best isolation values
Vibration isolation distinguishes between active isolation and passive isolation.
In vibration isolation according to VDI 2062, a distinction is made between active isolation, also known as source isolation, which reduces mechanical vibrations emanating from the machine, and passive isolation, also known as receiver isolation, which protects the device against influences from the immediate environment. Vibration protection with an isolating element can be divided into two types: isolation of periodic vibrations and absorption of shocks. Periodic mechanical vibrations result from imbalances of rotating machinery parts or mass moments of stroke movements. The isolation rate is dependent on the ratio of the excitation frequency (for example, engine speed) to the natural frequency of the vibration isolator (tuning ratio [η]). An isolating effect takes place only from a tuning ratio of η= √2; below this value an increased disturbance force must be expected. Damping [D] reduces the increase in disturbance forces, below η= √2 damping degrades the isolation effect. This means in practical applications that vibration isolating - both active and passive isolation - is a compromise between tuning ratio and damping.
Shocks are characterized by their strength, duration and behavior. They result, for example, from separating work in a press tool. The characteristic short, high-peak force is converted into a more protracted course with low residual forces. The cushioned system vibrates with the natural frequency of the vibration isolator. The lower the natural frequency of the vibration isolator, the lower the transferred residual force becomes. Passive isolating means to isolate machines (e.g. measuring machines) and machine parts against external disturbance forces. Theoretical analysis does not distinguish between active and passive isolation. Therefore, the isolation rate can be determined analogous to the active isolation.
In practical applications, passive isolation elements with low natural frequency are used. The excitation frequencies are usually natural frequencies of the floor in case of storey installations or low-frequency shock excitations. The best isolation values are achieved with LEVELMOUNT® air suspension units as isolating elements.