Abstract
This research has been carried out by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University in Elche.
This study gives a comparison between what occurs when braking on different Ministry of Transport (MOT) brake tester. We have analysed mathematical formulas about braking on bank of rolling and we indicate which factors should influence in brake on rollers in theory.
We have already study what occurs when many other parameters were changed like: tyre pressure, tyre tread, load etc... But now we study the influence of distance between rollers in brake and slip.
The car stops on the bank of rollers. The emergency brake should not be actuated. Then the rollers move at 5km/h of speed and we have to press brake pedal until we obtain 100% of slippage.This velocity is enough to obtain 100% of slippage. The pressure in the brake hydraulic circuit on the right wheel of the vehicle is also measured with a hydraulic sensor in hydraulic pipe of the right wheel. We can obtain the slip if we measure the angular velocity of wheel and roller. We obtain angular velocity from 2 encoders fitted one on the brake roller tester and the other one on wheel of the vehicle.
In Michel hernandez University we have two MOT bank of rollers, with different distance between rollers, where we have mesured brake and slip and we have compared the resoults with others MOT station with other distance between rollers, and we analyce the diference. We compare data acquired with theoric formulas to provide a new formula that depends on distance of rollers.
This paper demonstrates that the MOT brake and slide data results depend on the distance between rollers and we provide data and graphs to prove it.
Keywords: Braking, Ministry of Transport (MOT) brake roller tester, roller bed, distance of rollers.