Home
Generals
11. Vibration-damping elements
Download

TECHNICAL DATA AND GUIDELINES FOR THE CHOICE

Basic data required

  • disturbing frequency: the frequency of the disturbing vibration produced by a on-duty machine. In general, it is obtained by the number of rotations of the engine [Hz=r.p.m./60];
  • the load applied to every single vibration-damping element [N];
  • the isolation degree required [%];
  • the deflection value of the vibration-damping element under a given load [mm];
  • the rigidity [N/mm], that is to say the load that applied to the vibration-damping element produces a deflection of 1.0 mm.

How to choose the vibration-damping element

  • with reference to the diagram for checking the isolation degree, intersect the disturbing frequency value with the isolation degree required (each isolation degree corresponds to a line in the diagram) and define the deflection [in mm];
  • divide the load applied onto the vibration-damping element by the deflection value to obtain the required rigidity of the vibration-damping element;
  • compare the rigidity obtained with the rigidity shown in the table and choose the vibration-damping element which presents the nearest value (lower) to the calculated one.
  • the rigidity values reported in the table refer to the maximum load values.
  • the designer must verify that the article chosen through this selection criterion is suitable for the application required, in any case. For this purpose on request for each article, non-linear graphs of the spread (according to the applied load) are available.

Example

Conditions of use:

  • disturbing frequency= 50 Hz (3,000 r.p.m.);
  • load applied on each vibration-damping element 120 N;
  • 90% isolation required;
  • diagram shows that with a 50 Hz disturbing frequency and an isolation degree of 90%, the deflection obtained is 1.0 mm;
  • divide the load applied by the deflection obtained to define the rigidity required, which is 120/1.0 = 120 N/mm;
  • compare the rigidity value obtained (120 N/mm) with the values reported in the table;
  • the values reported in table, for type DVA.1, show that the vibration-damping element which should be used is DVA.1-25-20-M6-18-55.