Assignment

Nearly all garage testing devices show their results on computer displays. By dividing the results into graphic and numerical representation, the result is easily understandable for nearly everyone.

Function

A pre-requisite for the understanding of the analysis, is a knowledge of the function of the damper testing bench. Through the spring metal sheet between the engine and the bearings, the sensor can ascertain, first of all, the spring compression when driving onto the wheel plate. This is a measurement for the axle-weight. Apart from that, the left and right oscillations are determined by separate runs, from the high- to the low frequency area. The curves are shown in red (on the left) and blue (on the right) one on top of the other and at the same time, are numerically evaluated.

On the one hand, a not too large difference is important in the vibration behaviour of the dampers of one axle, on the other hand, the amplitude (oscillation width) may not be too large in certain frequencies (oscillation frequencies). If the amplitude on the left is too high, (in the high frequency area) the damping is too weak, if this appears on the right, (in the low frequency area) the vehicle is damped too hard. In the above shown case, the left damper is probably faulty.

If the Vibra-plates are close to the brake-testing unit, the two displays are also combined. The percentage then shown by the gauge, should be thus interpreted, that 70 to 75% corresponds roughly to the value of a new damper. Of course the values are, e.g., after 100.000 kms, very dependent on how the vehicle was handled, indeed, a good 60% is possible. Another advantage of the Vibra-plate, is that one might hear any other parts that are vibrating, and thus, be made aware of other damages. 12/12