This paper presents an example of shaping the vibration isolation properties of a passive seat suspension system. The object of the study is a mass-produced seat with a passive viscoelastic suspension, whose vibration isolation properties are shaped by changing the shape of the hydraulic shock absorber force characteristic, combined with connecting an air spring to an additional reservoir through a suitably selected pneumatic resistance.In the case of typical working machines that do not have a suspension, the operator’s seat usually remains the vibration-isolating element. There are several concepts for seat suspensions, such as a suspension consisting of a steel spring and shock absorbers working in parallel with it, or the currently widely used pneumatic suspension, in which the role of the steel spring is taken over by a pneumatic spring in the form of a rubber-cord bellows actuator [1], [2], [3], [4], [5]. However, all these suspension systems, without additional equipment, are classified as so-called passive suspensions, which do not show significant vibration isolation capabilities in low-frequency ranges; moreover, it happens that these vibrations are even amplified on the seat. Such a situation occurs when the natural frequency of the seat suspension is equal to the excitation frequency coming from the floor of the operator’s cabin of the working machine. (…)
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Source: Logistyka Magazine 3/2009